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Making the Classic quiet like a Mercedes-- Sound Deadening and Insulation

24K views 66 replies 15 participants last post by  turbotrenton 
#1 · (Edited by Moderator)
Well brief write up. Will tell you how it went although some pictures were skipped.

Things to know. Need 18mm 10 mm 15 mm and I believe 9/16 and a few other sockets. The 18 mm deep socket helps.
Need Flat head Screw driver for prying and some other items. And one hex allen wrench set for manual 4wd cover removal
May need a few other items but these will get you going.
 
#2 ·
Begin with the rear seat then the front seats and then middle console. This is for the best of both worlds in my opinion. The WT design with manual 4wd system and middle console that is undeterring for setting items and such. Can also park a kiddie in the middle if you really want too. But hey the insulation in these isnt too good. So I know how to improve that... :D The items for the Install regarding Materials are pictured below. R4 Cotton duct insulation wrap. You can do this with insulation that is peel and stick which is also fine if you want. Its thinner, and easier to place in some regards. I like the more insulation though.
 

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#5 · (Edited)
Then remove front seats then console and 4wd cover with Allen wrench. Mine has the rubber bottom which I have no problem with. If I do get a carpet insert oh well but I doubt I will. The rubber is fine and I pressure washed it clean before reinstalling. Id Recommend loosening the rear seat bolts. Then taking front seat area out. Then removing rear seat. "more flexibility for maneuvering"
 

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#6 · (Edited)
Below are ducts, insulation, and wiring. Remove these. The Wiring pulls up via connector ties, and unplugs. I vacuumed the insulation after it was removed. Then I cleaned the cab for a while because this was a cheap bought used truck to clean it up and stop rattling from change and items that have fallen in the past. .
 

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#13 · (Edited)
On the Middle Panels dont forget to spray foam the corners. The lower sides and such.

After you put in the flooring again and get seats back in I don't blame you if you drive and test it out. You will see 2-4.5 lower decibels if you do the thin layer duct insulation. I noticed about 4-6 decibels on this install with the cotton insulation alone. It was nice. Now on to the doors!
 

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#14 ·
Door designs have convenient hooks. You can do the peel and stick if your not worried about insulation. I did this because the WT body struggles in cold weather to hold the heat you want in the cab. Spouse was quite cold so this was to preserve the truck, lower the noise, and increase the AC efficiency. All three were easily accomplished.
 

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#15 ·
after these my truck had dropped about 5-8 decibels. The noise was incredibly reduced. Even on rough country roads it was quiet drastically compared to before. The only noise was the Engine which is great because I like the turbo spool. The ac fan as well. The Stereo never sounded better! It was a very worthwhile endeavor over the Christmas break! I noticed one noise however.... The Drive Shaft....
 
#16 · (Edited)
So I priced the parts..... Hmm... Then got two zip ties. Crawled under the steering wheel and zip tied the white bearing to the brake mount and called it a day! "FORUM HAS PHOTO EXAMPLE"

http://www.duramaxforum.com/forum/01-04-5-lb7-duramax-powertrain/38904-steering-shaft-bearing-2.html

No more rattle :D Drove the truck and it was a great experience! While many have much better trucks with sl, slt, packages if you think you will keep the truck for a while, if you really enjoy stereo, or less road noise, I would consider this down the road when you get time. Its cheap to do but time consuming. investment is about $150.00 Need 105 SQ FT of product "7 rolls" and one big roll of metal tape. If going all out get two! Get one container of spray foam for corners and to line truck chassis if you want.

Take your time, take breaks, have a friend handy "rear seat" and enjoy some music while your doing it. I had friends asking me for pictures while I was installing this and called me to ask how it was going. They were intrigued after the first few pictures. It was a great experience but, I am thankful it is over and I can enjoy it. Merry Christmas and enjoy. Just dont let it end cause the holiday ends :D
 
#17 ·
That's an awesome job! Correct me if I am wrong, but I believe a 5-8 decibel reduction is like cutting the existing sound levels in half. I wonder how the stuff you used compares to the automotive sound deadeners that are out there. I've been throwing around the idea of starting with my doors for now.
 
#18 · (Edited)
I drove it today. At 70mph on interstate "if turn off stereo and ac" I could only hear the engine and wind noise from travelling. I have also installed some weather stripping to reduce the wind noise however. I do not hear road noise at all. If on rough roads I can hear bumps but the drone and wheels are so quiet. The only thing you will pretty much hear is

1. The engine
2. Ac fan
3. Stereo turn it up however you want if you dont want to hear the others.
4. If you are running on interstate add wind.
I would say the road noise 40-50% reduced. I cant hear it hardly on the interstate. If you have gigantic mudgrip tires you will hear it probably but definitely muffled.
Bump noise at least 30% reduced maybe more on these. Its quiet. I hear the engine mainly.

The key to quiet this is to put the insulation deep in the front under the pedals. Since you quiet the cab so much with this be sure to watch your speed. You will think you are going slower because your cab noise is lower. Police will get you. If I turn off the ac and the stereo I hear the engine that's about it unless I hit back country roads.... Its a great ride.

Regarding the Drone of after market exhausts. I Barely notice this ever.... If on interstate can barely hear it if you try.... On back roads... Same.
 
#19 ·
Im glad everything worked out for you! Did you retain your moisture barrier in your doors?

From your findings, it seems that it will keep out some of the less intense sounds such as road noise, but mud tires may still escape through. I wonder if this is where the automotive sound deadeners kick in making them worth the extra $$$...
 
#20 ·
I have tires for the road so I hear nothing. Mud tires probably would be similar to the drone that comes through and the other deadeners may be better but I seriously doubt it. I think I have the best of both worlds. I only hear the engine if I shut off the Radio and Ac. Bumps if on back roads. Its quiet. Holds heat well. Did good with Ac too. Will have to see how it goes in the Summer. Try the alternative and see I guess.
 
#21 ·
The next level would be to take the same steps with the headliner and back panel of the cab.

What was the felt you used on the back of the door panels?
 
#22 · (Edited)
Look on page 1 for the felt. I used Insulation. On the Cab header Im not going to do it. It would require a peel and stick type. They dont last I hear. The noise is from the wind across the front and header insulation wont help much. I used foam and the header has insulation of a sort. The back panel I did like the doors. It works excellent! Personally I feel this is superior to the others in every way. Insulation + Noise reduction
 
#27 ·
So what I'm seeing on your door panels is the back side of the same foil faced stuff you used on the floor?

Blue, I'm where you are. I've done the butyl rubber adhesive foil backed on the doors already and it helped a lot. Different sound frequencies get attenuated in different ways. The felt/insulation type will help different frequencies than the adhesive type.

b-quiet has some good information on the science and even describes the types needed for our trucks.

https://www.b-quiet.com/

Trenton, keep up the good work
 
#23 ·
I have a feeling that I am going to go overboard with this. I might do an automotive sound deadener on the door skins and then the insulation on the back of the door panel. Hmmm...ideas, ideas...
 
#25 ·
I'll have to wait until it warms up again in a few months before I can get started. But when I do, this thing is going to be quiet!
 
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