How to quiet noisy back seat - Access Cab

Hey Guys,

I had pretty good luck quieting down the road noise coming from the back seat of my access cab, so I'd thought I'd share what I did.

It doesn't completely eliminate the noise, but I'd say it reduced it by at least 50% or probably more.

Step 1 - Follow the instructions for accessing the rear wall in this thread:

https://www.tacomaworld.com/threads/removing-rear-seats-and-back-panel-from-2016-access-cab.411587/

It's pretty straight forward but the bolt covers are difficult to remove without marring the surface, a normal panel removal kit won't do it. I used a feeler gauge to work behind the cover and then just kind of wriggled it loose from a corner. Others have reported success using cell phone tools designed for splitting cases/screens apart.

Also, if you break any of the red clips that hold the wall cover on to the back wall and don't want to wait for the exact replacement to arrive, I bought these from Autozone and they worked fine.



Step 2 - Seal the back vents.

I don't have any pictures because it's self explanatory, but I just used normal indoor/outdoor silicone sealant and applied generously between the edges of the black vents and the wall. I could kind of smell it for a day or so, but once it fully cured the smell went away. This is what I used:

$7 Loctite Clear Silicone Sealant, 2.7 fl oz, 1 Pack - 100% Waterproof Sealant for Glass, Ceramic, Wood, Plastic & More

https://www.amazon.com/gp/product/B0002BBX3U/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Step 3 - Apply sound deadening mat on the entire back wall. I had plenty of Noico left over after following the $250 audio upgrade thread, so that's what I used:

Noico 50 mil 21.5 sqft car Sound deadening mat, Butyl Automotive Sound Deadener, Audio Noise Insulation and dampening

https://www.amazon.com/gp/product/B012AVX5HQ/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

Step 4 - This is what I think is the most important step. Fill in the upper half of the wall with egg crate foam. People may be concerned about covering the vents, but it's open cell foam that allows air to flow through it without too much resistance so I don't think it's a problem. I haven't had any issues with windows fogging, poor airflow, etc.. since doing it. I put the eggcrate side facing the vents to help create space for airflow, that's the side that absorbs sound better as well.

This is what I bought. It's cheap and easy to cut to size. I only ended up using 4 squares.

Convoluted Green/Gray 2" 12" W x 12" L Egg Crate Panels Acoustic Foam Sound Proof Wall Tiles, 6 Pack

https://www.amazon.com/gp/product/B079YZWNG5/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Here's a picture of what it looks like after I installed it. You can see the Noico mat on the bottom half the wall, but I also applied it on the upper half that's covered by the foam. I also threw some left over pieces loosely floating around in the bottom half of the wall so that it might absorb some additional sound .. but I doubt it's doing anything.



Step 5 - Reassemble everything

I was able to put everything back together they way it came apart without issue. I kept the "curtain" that was originally there to help block sound, and installed it over the foam.

 

Love your egg crate idea. I will do that on mine for sure after I cover the entire back wall with sound deadener.. Heck if there's room, I'll egg crate the whole back wall.

 

I did that with my entire rig (doors, floors, back wall, ceiling) and it was a night and day difference

 

Did/do you have the rear diff howl? If so, did this help reduce it?

 

I just finished up mine, time for a test drive

 

I didn't have the howl, but I put a camper shell on the back and it really seemed to increase the windy/road noise afterwards. This helped quite a bit.

 

Looks good, how'd it do with the noise?

 

Remember that common egg-crate foam will absorb moisture - mold - then offer a nasty swamp smell. Try to at least find & use moisture resistant foam.

 

That's a fair point, but I live in the desert so I wasn't too concerned about it.

I don't think it's too much of a risk even in wetter climates if the vents are sealed up around the edges. That's mostly where I've seen water leak in. The cab is usually under positive pressure with conditioned air, so there's no more of a risk than mold/mildew growing in the carpet or seats.

 

"How to quiet noisy back seat" - put your wife in the front

 

That’s what the bed of the Truck is for.

 

It made it significantly quieter.