# 2008 Avalanche Midgate Sub Box/ Amp Rack Build. JL Audio



## Blister64 (Jun 13, 2010)

Hey just thought I would put up my progress so far on my midgate box build. This will be going in my newly purchased '08 Avalanche . I'm planning on taking a few days off and doing a complete install the second week of August, but this has to be done before anything can go in! Going just in the midgate will be (2) JL Audio 10W6v2's, (2) JL 500/1v2's, and (1) JL HD600/4. I pretty much have everything worked out the way I want, but if there are any suggestions, please let me know. 
Also, all pics so far were taken with my phone. Still ok quality, but better pics will be taken with an actual camera!

Here's my new toy:










So I started out by taking out the midgate, tracing, and cutting the shape out or 3/4 inch MDF. I'm planning on putting a W6 on each side, while having a cut out in the center to house the 3 amps. After looking at a few different ways to lay them, this was the best way, allowing room for the boxes to be built and still having a cool look to it. Note, midgate is upside down in the pic...










Next, I built the boxes for each of the subs. Although JL is right on with their box specs, I decided to go slightly larger for my box sizes. I decided to do this based on a few others doing the same to get a little more out of the low end sub base frequencies and having good results. JL recommends 0.625 ft^3 for the 10W6v2. I went with 0.7 ft^3. Not too much of a difference but hopefully I will get the sound quality I'm looking for. I also angled the boxes slightly so they would not hit the bar going across the cab while the midgate is lowered. I'm still wanting my midgate to be functional, so this was a must. I don't remember the exact measurements, but I think it turned out to be 9 inches deep up top and 12 inched deep at the bottom. 



















Edges are all angled with a table saw



















Everything on this box will be wood glued and screwed. No brad nails. It needs to be sturdy because I will be actually using my truck bed... Also need a dirt bike able to be tightened against the box. 
When screwing into MDF, I always counter sink and predrill my holes so there is no splitting.


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## Blister64 (Jun 13, 2010)

Got more of my Kicker 1/0 AWG wire in while working  This stuff is awesome...










Next, I positioned the boxes on the midgate cutout and traced there they would be going. I also made the circles for my speaker cut outs. I need a jasper jig 










Cut everything out and test fit subs.



















Next, I counter sunk and predrill all the holes for screwing on the boxes. At this point, nothing was glued. Everything will just be screwed in temporarily until all designs are final.


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## Blister64 (Jun 13, 2010)

The backs of the boxes will not be put on until later. Much easier to put caulk around the fronts to seal everything up when the back is not on!
After the boxes were put on, it was time to test fit everything and make sure there was clearance on all sides. 



















Fit perfectly  I didn't attach the mounts yet. That will come later. 

Next I cut out the backs of the boxes, made sure they fit, predrilled and countersunk all the holes. They will be going on later though. 



















Another cut out of the midgate was made to make my midgate box thicker, almost as thick as the original. This also will allow the subs to be flush mounted. I just attacked the 2 pieces with a couple of screws temporarily.


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## Blister64 (Jun 13, 2010)

The edge will be rounded off later. 


I cut a square out of the middle of the 2 pieces so the amps could be recessed and seen. It will eventually be covered with plexiglass, maybe some LED's thrown in there too somewhere to light everything up. 



















So I was trying to decide how I was going to mount all of the amps so that they could all be seen... I came up with the idea pictured below. I cut out a square the size of the space between the 2 boxes (if that makes since). Then I traced one of the circular cut outs I made for the sub on a piece of paper and cut it out so I could use the round edge as a template. I traced that shape on all 4 sides of the square piece, cut them out, and rounded the edges with a router. This allows the smaller HD600/4 to sit in the middle, while the 2 500/1 amps will sit below that piece, but still be able to be seen through the cutouts. 

Piece cut out










Rounded edges










This is the piece mocked up to see what it will look like once mounted. Thought it looked pretty good so probably gonna stick with it. Not completely centered...










So all that took me about 7 hours to do in a day last week. Planning on hopefully finishing it up tomorrow except for the cover piece going over everything and some other cosmetic things. I just need to get it functional and ready to go in the truck. Let me know what you think so far and if you have any suggestions, please post them! Thanks.


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## Brian_smith06 (Jan 31, 2008)

so far so good. Keep it up :thumbsup:


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## SSCustoms (Oct 16, 2008)

Nicely done! I really like the Avalanche. It may be my next truck.


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## getonerd (Jul 24, 2007)

SSCustoms said:


> Nicely done! I really like the Avalanche. It may be my next truck.


x2 i should have got one when i had the chance


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## Timelessr1 (Feb 12, 2010)

I love the design of the midgate in those Chevy's////the only problem is ....its still a Chevy...hahaha..just messing....awesome install so far!


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## Blister64 (Jun 13, 2010)

Timelessr1 said:


> I love the design of the midgate in those Chevy's////the only problem is ....its still a Chevy...hahaha..just messing....awesome install so far!


The midgate makes a great area to build a custom box! only a little room taken up in the bed... Almost reported your post until I saw you were just messing...  

Got some work done today, not as much as I'd like. Might still do some later though. Pics will be coming later tonight.


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## mr.metoo (Feb 20, 2010)

Looks amazing


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## Blister64 (Jun 13, 2010)

So I didn't get as much work as I wanted to get done today, but I pretty much finished up the amp rack and did a few other things. I'm still trying to figure out the best way to mount the bracket for the hinges on the top of the box (the stock hinges on the Avalanche midgate). 

I started off mounting the amp rack to the box. It will need to be able to be taken out for installing/uninstalling the amp when needed so it will not be glued in, only screwed. 

Pic of the backside










The spacer is there to allow enough clearance when the amp is mounted to have a plexiglass cover over the front of the opening. 










All secured up. I know it looks off center, but its not! There will be another cover piece going over the whole front anyways, covering the outer portion of the cut out. 










Next I cut the piece that will hold the 2 500/1 amps and connected them to spacers. I picked up some L brackets so no screws or holes would be seen on the front side. 



















Got it all screwed in with drywall screws. Only 2 were used on each side, at least one more will be used when it is in there for good. This piece will not be glued either because it will need to be removed for amp install/uninstall. 



















I went ahead and rounded the edges of the flush mounts as well. I'm planning on painting these as well as the amp rack area black, while the rest of the box will have a cover piece with vinyl over it to match the interior of the truck.


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## Blister64 (Jun 13, 2010)

Also got the boxes sealed up with some caulk and permanently attached to the midgate with wood glue/screws.

This is why the back's were left off. So much easier to caulk the front and sides! 



















Might seem like a lot of screws, but I really wanted these things to be sturdy. They will be holding up 3 amps in between them, as well as anything against them in the bed of the truck from time to time. 

This is where it gets exciting... For me anyways. I set the amps in the rack to see what they would look like. And I liked what I saw  
The cover piece will make the square window smaller on all sides by 1-2 inches, so the outer trims of the amp mounts and hopefully other things such as wires will be hid fairly well. After tracing where the amps were all centered up, I drilled the pilot holes and test mounted them to the racks. 



















That's all I got done today, but hopefully it will be completely done by Saturday, minus the cover piece and routes for the wires. I'll be happier once it is securely mounted in the truck... That's the next step. 

Any suggestions are welcome. Please let me know what you think so far! Thanks


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## Big_Valven (Aug 20, 2008)

I love this so far. Very neat and nice gear.
Only thing is, should have used a router jig to cut those woofer holes!

Can't wait to see it trimmed


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## BlueAc (May 19, 2007)

Very nice....


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## JP Fabrication (Feb 20, 2008)

22? Damn nice work so far.
Just a thought, how about removing your "X" amp rack, make a plate for the HD on risers that would attach between the 500's to give it the floating look. You could even mount the HD on a piece of plexi slightly bigger than the footprint and back light it.
Excuse my crude photoshop. 
Once again just my opinion. Your build is great so far.


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## ganesht (Oct 13, 2008)

Blister64 said:


>


Wow!


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## Timelessr1 (Feb 12, 2010)

Blister64 said:


> The midgate makes a great area to build a custom box! only a little room taken up in the bed... Almost reported your post until I saw you were just messing...
> 
> Got some work done today, not as much as I'd like. Might still do some later though. Pics will be coming later tonight.


Looking great so far! I have a new F150 and i wish they put a midgate in like that! I was even considering making a blow through in mine...but i dont know if i wanna hack up a new truck just yet! Keep the pics coming!


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## irishluder (Jul 24, 2010)

props man, very nice craftsmanship with the woodworking. I understand it looks alot easier than it is, very time consuming. Cants wait to see the rest


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## irishluder (Jul 24, 2010)

props man, very nice craftsmanship with the woodworking. I understand it looks alot easier than it is, very time consuming. Cants wait to see the rest


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## Blister64 (Jun 13, 2010)

Big_Valven said:


> I love this so far. Very neat and nice gear.
> Only thing is, should have used a router jig to cut those woofer holes!


I know! I need to get a jasper jig BAD! They actually turn out pretty smooth, especially after rounding the edges off. I'll be sanding them down, priming, and painting them black so they'll definitely be getting some attention soon...
To be honest, the actual box and amp rack is pretty much done as far as the structure. Made some cuts for the top, bottom, and back of the amp rack so it is completely enclosed, but didn't have time to attach them yet. The finishing work still needs to be done, but that night have to come later. I've been picking up shifts like crazy so time is hard to come by. The plan is to paint around the flush rings as well as all of the amp rack area. It will be painted the exact color of the truck (we have a body shop/paint booth for mixing and painting). I will be making another piece that will cover the whole midgate in the front that will be covered in black vinyl that will match the vehicle. It won't be 3/4 inch thick MDF, something thinner and much less weight. It will have cut outs a little larger than the flush mount holes, as well as plexiglass covering the amp area. Also have some LED's I'll be throwing in there somewhere. Planning on just somehow screwing the cover piece to the box, so there will be some sort of screws seen. If you have any suggestions on hiding them, please share. The back will be lined with bed liner to make it waterproof and somewhat match the rest of the bed. 

As far as how the box will attach to the truck... I'll take some pics of everything to show you later, but I'm planning on using all of the stock mounts and hinges. The hard part is the top where the latches attach to the crossbar (I know, I need pics, I will soon). The problem is that the bolts for these screw down from the top. MDF doesn't like bolts anyways, let alone trying to bolt something on one of the 3/4 inch edges! It will split like crazy with almost no force. These are what keeps the midgate tightly sealed and from flying forward, so they have to be very sturdy. My plan is to still use the bolts and still bolt them on the edges like the stock one, but I will be making some U joints the bolts will be going through. This will give plenty of support on the front and back sides of the box around the bolts so no splitting will happen when pressure or force is applied! I'll probably have to make my own since they need to have a 1.5 inch space between them... Planning on buying big L brackets and bending or welding them... Not sure yet, guess I'll have to see when it happens! 

I'll try to get some work done on it the next couple of days. Mainly need to get the U brackets made and everything bolted in. The front cover piece will have to wait until everything is probably in. No rush to make it. I am working the next several days, then moving, so bare with me with the updates. Thanks for looking.


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## Blister64 (Jun 13, 2010)

crnacnac said:


> 22? Damn nice work so far.
> Just a thought, how about removing your "X" amp rack, make a plate for the HD on risers that would attach between the 500's to give it the floating look. You could even mount the HD on a piece of plexi slightly bigger than the footprint and back light it.


Man I love your idea! Wish I would have thought of it! That would take some thinking about how I would make it stay, but I might look into doing that down the road... I'm gonna stick with the design for now just because I'm getting pressed for time with other things, and school starts later in August. Great idea tho, I'll be looking into it... 



irishluder said:


> props man, very nice craftsmanship with the woodworking. I understand it looks alot easier than it is, very time consuming. Cants wait to see the rest


Thank you. I've built a few other boxes before, but this is definitely the most complex. It's taking a lot longer than I thought it would, but it's worth taking your time and doing things right the first time. Measure twice, cut once!


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## ganesht (Oct 13, 2008)

Blister64 said:


> As far as how the box will attach to the truck... I'll take some pics of everything to show you later, but I'm planning on using all of the stock mounts and hinges.


for those of us who aren't familiar with the avalanche can you post a photo of the stock midgate?


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## Blister64 (Jun 13, 2010)

ganesht said:


> for those of us who aren't familiar with the avalanche can you post a photo of the stock midgate?


No problem, here they are. It was dark but you get the idea...

With the seats folded down, this is what the back wall (midgate) looks like. The hinges up top are behind the 2 bigger plastic pieces that go higher than the rest of the midgate. They attach on to the bar going across the cab. The lower mounts are under the rounded plastic parts at the bottom sticking out a bit. They bolt directly to the front side of the midgate.










The handle in the middle of the bar is what releases the midgate, very center of the pic. 










Here is what the top latches look like and how they attach into the bar going across the cab. Notice they bolt straight down the top of the midgate. The only way I can see to retain this is to use a U bracket for the box I'm making, allowing strength on each side of the box around the bolts. 



















Hope that helps. I'll be working on it some more hopefully tomorrow night and Monday morning.


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## Blister64 (Jun 13, 2010)

So I figured out how to mount the top hinges on the box today. Ended up going to Home Depot and buying some 8 inch braces to make U joints out of. They were only about $1.30 a piece. I'll need to drill some holes in the tops for the bolts to go through, but they should work perfectly. I'm planning of just putting a Nylock nut on the back side of the bolts to hold them. I'll route out an opening on the top of the box so the nuts are recessed in there. I'm not planning on bolting them to the actual wood. This will allow the mounts to move side to side, meaning I won't have to measure the exact distance between the hinges. They are only there to make sure the box is snug and won't fall, so it should work fine. Here's the pics of the process. 

Made marks on each side where the board ended (1 1/2 inch gap) to bend the braces. Used a ruler to do this to get the exact center of them. 










Moved out of the basement and into the bodyshop for some equipment more suiting for the job.  A vice and sledge hammer worked perfect! This stuff was actually VERY hard to bend. Not a bad thing, just means it will be plenty strong for supporting my box. 










After some hefty swings...




























Next I went to test fit them. One of them was perfect, the other was _slightly_ too small, but I got that fixed real quick and they both fit nicely. 




























I'm one step closer to getting this thing in! Sucks that all the tools to build this are at my parents house 45 min away from where I live... More to come soon. Thanks again for looking and comments/suggestions are welcome.


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## Blister64 (Jun 13, 2010)

Out of town for the next week. Full system install when I get back though!


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## Punkdcrew11 (Aug 7, 2010)

cant wait to see how this goes. im about to start a build on my avalanche too. going with a midgate ported box with 2 mtx 9500's 3 amps and a 2nd battery. curious to see how the mounting goes...
now with you having a 1.5" face are you going to have to add extra blocks to the hinge to make a seal on the midgate?


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## Blister64 (Jun 13, 2010)

Punkdcrew11 said:


> cant wait to see how this goes. im about to start a build on my avalanche too. going with a midgate ported box with 2 mtx 9500's 3 amps and a 2nd battery. curious to see how the mounting goes...
> now with you having a 1.5" face are you going to have to add extra blocks to the hinge to make a seal on the midgate?


It actually was about right on. I just bolted the stock hinges on the bottom to the front face of the box, actually used 2 washers to make it seal a bit better. It sealed up fairly well, but not as tight as I'd like it to be. Even though I don't plan on leaving the covers off the bed, I don't want any water getting in at all. Eventually I'll probably cut out 1/4 or 1/2 inch strips to go on the back side of the box right where the seal is. Or add some weather stripping on the back where the original seals are. Then it would be very tight. 

I just finished my 3rd 14 hour day in a row doing the whole install. I've got a couple more hours on it and everything will be in! All that's left is installing all of the amps, mounting them in the box, installing the subs and tweeters, and tuning a bit. It's been a rough past couple days, it nice to see it coming together!! Pics will be posted soon of everything in and the process.


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## Blister64 (Jun 13, 2010)

Well I actually have everything in and it's sounding great! There's some bad news though... It's at the dealers getting new valves and lifters. It's all under warranty though so there will be no selling of the system to pay for it! 

I'll get some pics of everything soon, hopefully later today.


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## Punkdcrew11 (Aug 7, 2010)

well ive been building my box for about four days in between work. here are some pix. ill make a build thread later with some more details. 

Pix Link


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## lowbudget (Aug 15, 2010)

i see you or your parents have a scag mower nice machine and nice build by the way


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## Punkdcrew11 (Aug 7, 2010)

You mean a toro?


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## lowbudget (Aug 15, 2010)

no the orange mower in the hinge fab pics is a scag pretty sure i work on them for a living among other things


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## Blister64 (Jun 13, 2010)

Punkdcrew11 said:


> well ive been building my box for about four days in between work. here are some pix. ill make a build thread later with some more details.


I like it! Love what you did with the body putty around the speakers to give it the curves. Def post on here when you make a thread so I can check it out. Making a write up of mine now with the pics...


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## Blister64 (Jun 13, 2010)

From here on out, I'll be posting about the entire build, not just the box. Is there a way to change a thread name? Thought I'd ask... 

I'll be installing:
Pioneer AVH-P7800DVD 7 inch flip out DVD 
Hertz Audio HSK 165XL components 
Hertz Audio HCX 165 coaxs
(2) JL Audio 10W6v2's
(2) JL Audio 500/1v2's
JL Audio HD 600/4
Kicker Power Wire and RCA's
KnuKonceptz 12 gauge speaker wire
(I think that’s it…)

I also did some paint work on some interior parts.

So lets get started... 

First was the tear down stage. I took out all of the interior wood grain pieces to paint black, as well as both chevy bow ties on the front grill and on the tailgate. Took the dash apart and out, rear seats out, midgate out, trim panels along the doors out... Was going to take the front seats out, but GM makes a specific tork socket that unbolts the seats. Didn't have a single socket that would fit it in out body shop, nor did any body parts place in town. Snap-On tools could order me one that would arrive in 2 weeks... No thanks. Took the door panels off as well and removed the ugly wood grain window and lock covers.
































































Now for some paint. I primed all of the wood grain pieces and the bow ties to be painted the black color of the truck. I also decided to paint the dash kit black as well, not pictured.


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## Blister64 (Jun 13, 2010)

When I took the door panels off, I was met with a little surprise. Apparently the avalanche doors do not have mounts for a regular 6.5 inch speaker. The stock speakers are in a plastic case that snaps in and has only 1 bolt at the top. I don't have a pic, but the plastic cases were not usable either, the speaker was actually built in it. Weird. So I had to make my own mounts for the doors. I ended up just tracing the shape of the plastic speaker mounts, making them slightly wider in just a few areas, and cutting that shape out of 3/4 MDF. Those were then aligned over the speaker hole in the door and screwed in the sheet metal with self tapping screws. 

This is the kinda odd shape for the speaker hole










Speaker mount secured to the door










This is the HSK 165 XL's going in the front. 



















A pic of the fronts in



















Rears in










This happened later in the build, but since I'm on the subject... The door panels on the rear doors didn't exactly fit with the new rings I made. The part that housed the mounting tabs on the door panel was hitting the wood rings, so I had to shave them down a bit with a grinder. They just barely hit, so it wasn't much.

Before. The parts closest to the speaker grill need to be ground down a bit










After being ground down, they fit perfect!


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## Blister64 (Jun 13, 2010)

Now for running all of the wires. Found a big ribber grommet on the driver side firewall to run the Kicker 1/0 gauge wire through. We ended up running it down the center of the car under the center console because there wasn't much room to work with along the doors. Cut a small slit in the carpet right by the rear of the center console and fed the wire under the carpet from there to the back. Couldn't really even notice is there. 










Also ran all of the speaker wire to the doors. It was kind of tricky to get the wire through the door wire boots, but we found a way... 

The truck already came with an extra Yellow Top battery, so that was used to power everything. Besides the 1/0 wire powering the amps, it has a 1/0 gauge wire going to the motor block ground, 1/0 wire going to the alternator, and a 4 gauge wire connected the positive terminals to the stock battery as well. 



















Next we worked on getting the head unit installed. The pioneer 7800 has a hide away unit, so had to find a place for it. Fortunately, after taking the stock Bose sub out from under the center console, there was plenty of room for everything. 










After all of the wires were ran and tied up.










All those wires are a mess btw, that's the worst part about that unit. Love everything else tho 

It took a while to get all of the wires hooked up and working, but here is the head unit in and all of the trim pieces back in place. 










I'll get more pics of the dash and HU up soon.

Next we got all of the power and ground wires ready for the amps. Ended up a Tsunami 1-3 fused distribution block. It uses mini ANL fuses, put 50A fuses in. For the grounds, I just used the Kicker distribution block that came with the wiring kit. All power and ground wires are 4 gauge to the amps, then fed into 1 gauge at the distro blocks.


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## Blister64 (Jun 13, 2010)

So after all the wires were ran and everything else was in, it was time to get the box ready to install. I drilled and tapped holes for the bolts to hold the hinges on the bottom. They won't be under any pulling stress so the threads should hold just fine. They are more supporting the box upright. Ended up putting 2 washers with each bolt to snug up the seal on the back side. I'll end up putting some weather stripping on the back as well to completely seal everything. 



















Test fitting 



















Next I needed to attach the pieces on top to go into the latches. This will hold the box upright. 










After test fitting and measuring gaps, I ended up taking the bracket's I made earlier in the build and drilling out 2 holes for the bolts to go through. Put a nut on the back side, tightened them down, and they were good to go. 



















The top of the box had to have some holes drilled out so the bolts could go down. After that was done, everything fitted up perfectly. The box closes completely and opens with no problems. The only issue is that it does not lay down completely. It will go a little past 45 degrees before it hits the rear seat hinges. No big deal though, don't plan on it needing to go down. 

All bolted in with latches working on the top


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## Blister64 (Jun 13, 2010)

After everything was fitting correctly, the back of the box needed to be sprayed with truck bed liner to make it water proof. I don't plan on leaving the covers off of the bed, but there is still some water leaking when you go through a high powered car wash. Plus I haul my dirt bike and might get caught in the rain sometime... I ended up using Duplicolor's spray on truck bed liner. It was only about $9 per can and 2 of them gave me 2 coats over everything.

All taped up and ready to go



















After the first and second coats



















This is the back side with it installed in the truck without the middle cover piece. The cover piece will be removable because the amps will have to be installed through the rear of the enclosure. 










This shows how close it was to be able to open. It works, but I'll have to trim the back cover piece down just a bit to make it work. This is without the rear piece. It's tight!










Next I put the tweeters in. I decided to not use the stock location, which is on the pillars pointing towards the windshield. Instead, I used the cover pieces on the door panels that cover the side mirror bolts. I just flush mounted them for now, so they are more of an on axis set up. Eventually I'd like to do some fiberglass work on them to direct them better. 

Cover location










Traced the size of hole I needed on the back side


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## Blister64 (Jun 13, 2010)

Drilled a hole in the center and cut out the hole with a dremel. Best way I found to secure them was with a vice and clamps, the towel protecting the front. Then sanded with 80 grit then 220 grit sand paper. 



















Used the flush mount trim ring and back piece provided with the Hertz tweeters. Put the foam back on the back side of the covers and reinstalled.




























Looked pretty damn good I thought! Almost looked stock.

After all of that, I installed the subs and amps. Tuned the mids with a digital multimeter, but found that tuning the subs by ear was a little better for me. The subs have about a 0.7-0.75 cu ft box each, and they each have 1 pound (1 package from walmart??) of polyfill. Holes were drilled on the side of the box by the amps and the speaker wire fed through and caulked up, so no connectors were used. 

After everything was in and tuned how I liked, it sounded AMAZING!! I know it's my truck, so I'm probably partial to it, but I couldn't be happier! The Hertz speakers are extremely clear and just get louder and louder, no distortion that I can tell. The bass is awesome as well. The JL's have amazing SQ and get damn loud, even for just 2 10's. I listen to mainly rock, and the bass kicks are intense! This was the biggest project I've done so far, and it definitely took some time, but I'm loving the way everything turned out!! 

I know I need some more pics of everything installed in the box. The truck is currently getting some warranty work done on it, but as soon as I get it back, more pics are coming! The box still needs a cover piece to be made to make it look nicer and to hide the wiring, but that's probably going to have to wait until school is out for a bit. I'll get some pics of the HU in the dash as well. 

I'd also like to thank my friend Drew for coming up from Columbia to help with the install. I couldn't have gotten it done nearly as quick without him! As well as some killer deals on equipment... 

Let me know what you think so far and I'll work on getting the other pics up soon. Thanks!


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## Punkdcrew11 (Aug 7, 2010)

great write up! looking clean. yea i always do my tuning by ear as well, easyer for me and its gatta sound better too.


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## Blister64 (Jun 13, 2010)

Punkdcrew11 said:


> great write up! looking clean. yea i always do my tuning by ear as well, easyer for me and its gatta sound better too.


Thanks Punk (lol). Yea tuning the mids is fine with a meter to get a base volume set, but getting the bass to blend well takes listening to... I actually tuned the rears slightly lower since it'll just be for fill sound if there is anyone in the back. How's your box coming along?


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## Punkdcrew11 (Aug 7, 2010)

I've been working too much haven't been able to do anything. And I can't decide if I want to have like a bodyshop paint the face of the box or just paint it all with a bed liner of somesort. I still have to build amp racks under the rear seats and do alittle more wiring. And today my HU quit working. I think it blew a fuse or something when I was using onstar.


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## Blister64 (Jun 13, 2010)

Punkdcrew11 said:


> I've been working too much haven't been able to do anything. And I can't decide if I want to have like a bodyshop paint the face of the box or just paint it all with a bed liner of somesort. I still have to build amp racks under the rear seats and do alittle more wiring. And today my HU quit working. I think it blew a fuse or something when I was using onstar.


I hear ya. I barely had time to finish all of mine with work. It'd be way cheaper to use bed liner, but your pretty much stuck doing that if you do. Have you thought about vinyl? I think it would look good with a darker gray or black vinyl, that's what my cover piece is going to be. I'll be painting the inside of the amp rack though. Sucks, if you lived closer I'd could paint your box pretty cheap for you! One good thing about vinyl is that it would probably hide any waves on the flat surfaces of the box a little better than shiny paint. Let me know what you decide to do with it.


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## Blister64 (Jun 13, 2010)

Punkdcrew11 said:


> cant wait to see how this goes. im about to start a build on my avalanche too. going with a midgate ported box with 2 mtx 9500's 3 amps and a 2nd battery. curious to see how the mounting goes...
> now with you having a 1.5" face are you going to have to add extra blocks to the hinge to make a seal on the midgate?


Hey Punk, looking at your pics, it looks like yours is a little thicker than 1.5". How thick did you end up going? Mine touches the seal, but it's not really tight so I'll have to put weather stripping on the back side. Might decide to add blocks later. How did you decide on your thickness too? I thought I measured about 1.5" but I think it seals a little further up the midgate where it is a little thicker


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## Punkdcrew11 (Aug 7, 2010)

i used two 3/4'' for the face (1 1/2'') then i put that extra 3/4" border on the bottem and top. i notched out about a 1/4" for the henges and rounded out the top peice well so it wouldnt stick out. it seals pretty well but i think im going to cut out some of the plastic thats below the weather stripping to butt up alittle closer. if you notice the factory midgate is sloped so that it doesnt rub the plastic and gets tighter to the stripping. the box mainly rubs on the bottem corners, im sure if i cut some of it out it will give just a little more seal.

i decided that im going to wrap the box with a vinyl fabric. like you said its going to hide alot of the curves and imperfections. i should be starting on that tomarrow already bought the fabric, adhesive and some extra staples. then going to be painting the backside with bedliner.

i made this awhile back for a different box, got it all realy smooth and sanded down. i want to incorporate it into this one. i think im just going to cut it in half and put on the backside of the boxes. 
















lmk what you think


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## Blister64 (Jun 13, 2010)

Gotcha. Yea mine rubbed slightly on the corners but not enough to do anything. Let me know how your vinyl goes on. I haven't done it yet but I know the materials I need to get. Did you get 4 way stretch vinyl? 

I like the flames! Where do you think you'll put it? Oh, backside, got it. I think it would look pretty good as long as your not planning on putting anything back there that would damage it. It'd be cool to somehow either put a chevy bow tie in the center of it or write avalanche, something like that. I'd say go for it though since you already have it cut out and ready to use. You def gotta do a build thread of your own! I wanna see more pics!


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## Blister64 (Jun 13, 2010)

Here's the rest of the pics with everything installed. I know there are wires all over the place, but I will be making a cover piece to go over it, as well as making some cuts to route the wires a little better. 

Back of the box










Front side




























Here's the amps. Everything fit up really nice. I'll have to hide the wires behind the X piece as well as cut some notches out of the bottom of the square, but at least it's in while I'm in school for the fall. 



















Here is the head unit in the dash with all of the truck trim pieces painted black, including the dash kit. It's a Pioneer AVH-P7800DVD. Amazing head unit. Has a great sound, equalizer, added BT for phone, and is very easy to navigate through the menus. I've been extremely happy with this HU. 




























Well that's it for now. Eventually I'll probably do a little fiberglassing where the tweeters are to position them better. I've got some other things in mind as well for the truck, but nothing audio related at this time. Thanks for checking out my build and let me know what you think!


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## Installer4life (Jun 26, 2010)

Nice job. I don't think I have ever seen that many wires in one location but at least you had a good spot to hide them and get them out from behind the radio...


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## Blister64 (Jun 13, 2010)

Installer4life said:


> Nice job. I don't think I have ever seen that many wires in one location but at least you had a good spot to hide them and get them out from behind the radio...


Thanks man. No **** about the wires... Like I said, worst thing about the HU is hiding them all! There were 3 or 4 of the thicker wires running from the HU, including the power/ground/remote wires and the FM antenna wire that runs to the hide away unit. Apparently they expect you to put the hide away in the rear of the vehicle because every wire is probably 20 feet long! I actually did put it behind the seats in my last vehicle. It went where the stock sub and amp were located in a 2000 BMW M Coupe. At least there was some space after the stock sub was taken out in the Avy... PITA though!


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## philgood3213 (Jun 13, 2011)

sweet set up man. i built a midgate box for my '04 and havin some problems and questions. The plastic panels that go along the door and the door panels rattle real bad do yours? and the mdf soaksup any moisture that gets in the bed, so even a small leak seeps up from the bottom and makes the mdf bubbly at the bottom prolly 2 in. but i did use weather stripping along the edges and used a rasp to slope the edges that rub on the plastic pieces on the bottom and make a better seal. (holds out the water from the cab that leaks through the bed really well tho.) Did you use 3/4 in mdf? i did and its SOOOOOO HEAVY! thinkin about maybe taking it apart and using fiberglass for the back part of the enclosure (or the front who knows lol) you think that would be a bad idea?

thanks man


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## viscious350z (Jun 30, 2011)

Awesome work...


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## Blister64 (Jun 13, 2010)

philgood3213 said:


> sweet set up man. i built a midgate box for my '04 and havin some problems and questions. The plastic panels that go along the door and the door panels rattle real bad do yours? and the mdf soaksup any moisture that gets in the bed, so even a small leak seeps up from the bottom and makes the mdf bubbly at the bottom prolly 2 in. but i did use weather stripping along the edges and used a rasp to slope the edges that rub on the plastic pieces on the bottom and make a better seal. (holds out the water from the cab that leaks through the bed really well tho.) Did you use 3/4 in mdf? i did and its SOOOOOO HEAVY! thinkin about maybe taking it apart and using fiberglass for the back part of the enclosure (or the front who knows lol) you think that would be a bad idea?
> 
> thanks man


Hey man, I used 2 layers of 3/4 inch MDF for the main wall. If you take your box out and use some spray can bed liner like I did, water won't be an issue whatsoever. Just do it on the back and around the edges. You can do it on the front too, was thinking of doing that if I ever took it out for some reason. My plastics don't really rattle too much, but if they did I would probably just get some thin foam (kinda like a 3M double sided foam tape) and put it on the backside where the plastics were rattling. Did that trick for license plates in the past, works great. Thought about the fiberglass too, actually did some fiberglass work after making that box. It would def make it lighter, but I'd have to do some thinking about how I would do it. It can be done though!! 

Appreciate the comments, thanks! It's still hittin hard! I've actually strapped 2 dirtbikes in the back against the box and had no issues either. Mounts aren't bent and still holdin strong.


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## indytrucks (Apr 5, 2009)

Those latches are a pretty cool idea. Good looking install.


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## Cali_Screw (Aug 26, 2008)

boxes look a bit small but very nice!


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## Blister64 (Jun 13, 2010)

Cali_Screw said:


> boxes look a bit small but very nice!


Actually they ended up being just slightly larger than want JL recommended for a sealed enclosure plus they have polyfill in them. I went with the smaller sealed enclosures vs ported ones because I wanted to have my amps on the box too and I wanted the least amount of space taken up in my bed because it is used often. That spray bed liner has held up great! Only lost 12" of space at the most of my bed at the very bottom of the boxes I


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## Salad Fingers (Jun 14, 2009)

Well at first I was just thinking it was just going to be a generic install, but then I was like 'yea, yea' as things went on and I started getting a little excited about what was to come. It got all the way there, and then just stopped right before it all came together!!! Man, this is a cool idea and executed well. It would be really cool looking if you just hide the wires behind the X and make a little notch in the bottom for the few wires coming it there (like you mentioned). Then, wrap the fascia in maybe a black vinyl or suede or even a dark "Chevy" like carpet even, and then wrap the X in like a lighter silver vinyl or suede that is close to the amps brushed finish. There is even a cool brushed looking vinyl that you can get that is really cool too! Do it!! I want to see this vision complete!!

If you are a flashy fella, you could put some led or neon (kind of unreliable in my experience) lighting behind the X.


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## Blister64 (Jun 13, 2010)

Hey thanks salad fingers. I've been wanting to finish it off a a little cleaner... I am going to eventually!! I have school during the fall and spring semester and been working my ass off during this summer. It'll be a project for either Christmas break or spring break. I doubt I'll get to it before school starts. I think I'll hide the wires behind the X like we've said, and the probably just make a slanted cover for the wires at the bottom of the box so it doesn't look like a disaster down there. Planning in either covering the box in vinyl like said or I'm thinking about doing the bed liner on the inside too. I'd probably paint the X black like the truck (instead of silver) because the amps are already silver. Gives it a bit of a color contrast. I'd just prime it and auto paint it. The only thing stopping me is it's a b!%$& to take out! It's pretty damn heavy.. But for now, it sounds great, the back is protected by the elements, and the wires don't interfere with anything. But soon...

So thoughts on using bed liner on the inside too? The idea is really growing on me. Cheap (under $20 for 2 cans), rugged, and the textured look more matches the interior trim (vs smooth painted).


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## Blister64 (Jun 13, 2010)

well the time has come to finish the enclosure up. In the next few day's I'll be painting the rest of the box with bed liner and hiding the wires. Mostly. To completely hide them will take a little fiberglass fun at a later time. hopefully no issues!


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## Blister64 (Jun 13, 2010)

It's finally done! Wooooo! I should have done this before I ever installed it the first time... O well, lesson learn! 

Spend the last 2 days finishing up the paint work and hiding the wires at best I could. Instead of covering the interior part of the box with vinyl or other material, I decided to just stick with the Duplicolor truck bed liner. And it turned out great  Here are some pics of the build...

First of, here's what I was looking at before I started. Enough wires??










After taking it out, I made some cutouts at the bottom on the box for the wires to set in on their way in/out of the amp rack. There wasn't any other way for them to go less noticeable. Trust me... 










I prepped the surface of the box by mainly just sanding down all of the edges to give them more of an angled look instead of a corner. Smoothed down any rough spots with 80 grit on a DA sander. This is after around 2-4 coats of the Duplicolor brand truck bed liner. After using the stuff on 3 other builds, I've gotten a pretty good technique to getting a uniform texture on the box surface. The trick is to apply LIGHT coats. I hold the can back about 2 feet and move it fairly quickly so it doesn't pool in one area. If that happens, the paint bubbles real bad (for whatever reason, chemical reaction after being sprayed) and the texture is smooth with small bubbles in it. Anyways, got it lookin good. 



















Nice texture 










Just put it in, already lookin much better!










This is the back plate that the 2 500/1v2's sit on. This and the X that the HD600/4 sit on were also both sprayed with bed liner. I cut notches out in the lower corners of the X and drilled holes in the back plate for the wires to go through and come out right where they will be connected. Learned that from my countless hours of looking up threads on here lol... 










Here's the back part of the X with all of the 4 channel amp wiring ran. Nice and clean


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## Blister64 (Jun 13, 2010)

Here's a pic of the back amp plate with the wires and what the back looks like after it was installed. The back cover plate that is bed lined still needs to go on. 



















And here it is! All installed and lookin good! I ended up putting the lower trim piece back in to hide the wires going under the carpet. Also put the hinge covers on to hide the hinges (duh) and cover more of the wires going into the box. This was the best I could do without making another cover piece. Looks much better than before!! I might look into making a cover piece out of fiberglass that attached to the hinge covers for the rest of the wires. Maybe another day 

It turned out great, the texture and color almost exactly match the side panels and other trim. Looks like it was made to be there! I'm pretty happy with it. Let me know what you all think and thanks for checking it out!


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## Blister64 (Jun 13, 2010)

Oh yea, I also put some rubber molding along the backside of the box where it meets the stock seal. This will make the seal tighter and shouldn't let any water leak through. I didn't have issues before, I just couldn't run it through an auto car wash because the heavy blast of water would make it leak just a bit. Rain wouldn't do anything. Hopefully now, there won't be any issues even with the car washes.


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## Wacky7 (Jul 7, 2011)

Awesome job. this look nice bro. Now you need a some subwoofer grills. I kinda wish you did fibreglassthe back of the box and maybe fibreglass your hinges or add a cover for it and add some wire holders make it little extra good looking.But it sharp. I like it


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## Blister64 (Jun 13, 2010)

Thanks man. I'm thinkin I'll do something eventually for the wires... What do you mean fiberglass the back of the box? And I have 1 grill for the W6, but would have to buy another. I kind of like the look without them though. I had the grill in the back of my M coupe when I had it in there because I used my trunk and didn't want it getting hit. In my truck, nothing goes behind the seats and the only reason I even lower the rear seats is to look at it lol.


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## Angrywhopper (Jan 20, 2010)

I would LOVE to see pictures of the M coupe audio build. I'm a huge ///M fan (on my 3rd M3 now )


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## Blister64 (Jun 13, 2010)

Angrywhopper said:


> I would LOVE to see pictures of the M coupe audio build. I'm a huge ///M fan (on my 3rd M3 now )


It wasn't anything too special. I actually don't have any pics of what was in it come to think of it. I had the same HU in it as I have in my Avy, Hertz Dieci Comps in the stock locations, and 1 500/1v2 and 1 10W6v2 with the JL prowedge box in the trunk. Hid the amp where the stock sub was. It was a fun car, fast as hell. Like my truck much better though. I'm 6'5" though, so I looked like a giant next to that small thing! Here's a few pics since your a fan. The stereo is an OLD panasonic POS that I put in it to sell. No way was I gonna give up my Pioneer. $850 lost if I did that. 























































Oh, did I happen to mention that we bought it after it was rolled over? Chopped off the roof halfway up the pillars and replaced, body work on almost every panel, complete paint job. Worked on it with my dad. I've never seen a smoother paint job than on that car  Makes factory paint look like it has craters in it... Can you tell it had the roof cut off??


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## Angrywhopper (Jan 20, 2010)

:drool: car looks great. I have always been a huge fan of the M coupe. 

And no, I couldn't tell the roof had been chopped off.. Good work on bringing her back to life! 


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## Blister64 (Jun 13, 2010)

thanks man. My dad's been doing that kind of stuff for over 30 years. I've been learning body and paint work ever since I was 15. I enjoy it, you learn something new every time you do it!


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## Blister64 (Jun 13, 2010)

Well I decided to try my hand at some actual tuning...  

Tried switching polarities on the front stage. Ended up with only reversing the passenger tweeter. If I switched 1 or both of the midbass, I lost almost all midbass frequencies with no real stage improvement. Switching only the right tweeter really made the sound stage raise up and move forward a bit. Instead of hearing the center of the sound coming from the center of the radio, it was coming from the top of the dash or bottom of the windshield. Instant improvement! 

Then I tuned each frequency to the center on my HU. I'm really starting to enjoy all the functions of it! It has a 13 band EQ and I used the Focal tools CD test frequencies to adjust. I got everything sounding pretty good. It's amazing how far off center certain frequencies can be even though you "think" you've centered it with just the L/R adjuster. Also equally amazing how certain frequencies can raise or lower the sound stage. It's probably not perfect for everyone, but it sounds so much better to me! It was almost hard to get used to hearing the sound come from a "higher" spot lol :laugh: 

Here's the EQ difference between each speaker. Quite a difference to get everything centered.



















Thinking about putting some sound deadening in the door panels at some point. Not a huge priority right not because of money. And it'd just be the doors, not the floor or roof.


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## Kerpal (Jan 27, 2009)

Great build!


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## phryed (Aug 5, 2011)

Great build i especially like how you mounted the amps. thanks for sharing!


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## Blister64 (Jun 13, 2010)

Thanks man. Oh, and an update. I realized the next day after tuning that it sounded like crap... An hour wasted lol. I ordered the mic adapter I needed for the TA and auto EQ and recently did that. Amazing difference! It's crazy how much better and more balanced things can sound with a proper tune! Just finishing up on a simple build for my little bro's truck, so expect to see that on here soon. First time using carpet so we'll see how that goes...


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## FLYONWALL9 (Nov 8, 2009)

I'M IN....

I like the amp rack creativity, very unique. Good job!

Cheers,
Scott


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## topedge (Nov 1, 2011)

Very nice work! We have a custom shop ourselves and sell a lot of Avalanche Sub Boxes. Would like to offer one like your's! You definitely pay attention to detail and I love JL Audio.

Good Job!


Mark

topedgeonline.com


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## Blister64 (Jun 13, 2010)

topedge said:


> Very nice work! We have a custom shop ourselves and sell a lot of Avalanche Sub Boxes. Would like to offer one like your's! You definitely pay attention to detail and I love JL Audio.
> 
> Good Job!
> 
> ...


Thanks Mark! I wanted something a little different from what I've seen and actually have the amps off the floor. Don't worry about damaging them that way! Good luck with your shop and thanks for the compliment!


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## FreddieG (Apr 30, 2011)

Man that install is awesome...I just got a 08 AVy too. Do you step by step instructions on how you painted the interior peices? I hate that wood crap too.


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## Blister64 (Jun 13, 2010)

FreddieG said:


> Man that install is awesome...I just got a 08 AVy too. Do you step by step instructions on how you painted the interior peices? I hate that wood crap too.


I can write something up here soon.. Yeah those wood pieces are horrible! Congrats on getting the Avy! I love mine!


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## AvalancheDave (Jan 18, 2012)

what a nice job!


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## Blister64 (Jun 13, 2010)

Installed a backup camera that comes on when you put 'er in reverse. Did that probly 6 months ago, just never updated anything. Man I was looking back through this and was just think how big of a PITA taking all that interior apart was! Glad its done. Still going strong!


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## Blister64 (Jun 13, 2010)

So I haven't been on here in a while and thought I'd check it out. 

This thread has over 20,000 views!! That's incredible! The build was definitely challenging but very rewarding in the end. I'm glad so many people have taken a look! Hope I've helped some of you guys out and given you some ideas, especially for the Avalanche owners! Thanks!


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