Terrible road noise / cabin noise in my new 2016 2500 HD

George C · July 28, 2016

Road surfaced affect the sound, so I think we can rule out drive train components. It's tire noise that's being transmitted into the cab. I highly doubt tire brand affects this either. Somewhere, there is a breach in insulation.

Definitely NOT as quiet as my last Super Duty.

H1ghlndr · July 28, 2016

Great stuff.

I am considering the inner fender well liners next as they seem like the might translate noise/resonate up through from tires.

What do ya'all think?

wrc7732 · July 30, 2016

Check for missing plugs in the floor. I remember and issue in the past where cars have had interior NVH issues due to plugs associated with shipping not being reinstalled by the dealers prior to delivery.

Second:

The Lexus LS460 I used to own had a similar issue. There were multiple things that contributed. One thing that made the biggest difference was that the drivers door panel was not fully seated in place and sound was coming up through the door panel between the glass and the inner door panel seals. Other noise was associated with wind getting trapped around the plastic trim surrounding the windshield on the outside.

I agree with the prior two posts that wheel well liners would be a good place to start. There are also plenty of penetrations through the firewall that could have improperly installed/placed grommets, or gaps in the insulation. If nothing is apparently wrong with the fender well liner, perhaps remove it and look for issues behind it. Open the door and look for plugs out of place.

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Greg Stevens · July 31, 2016

My mechanic mentioned a few possible reasons, but mostly, he thinks a combination of 'thinner' steel and materials in the body and lack of insulation in the firewall. He recommended, and this sounds odd, packing a bunch of pink home insulation in the engine compartment between the engine and the firewall to see if it makes a difference. Hey, we're all getting desperate, so nothing to lose. Gonna try it this week.

Wanna2500 · August 3, 2016

I have 3K miles on my 2500 Denali and know exactly the road noise you are talking about. Mine goes from non existent to very noticeable based entirely on road surface. I have put Michelins on and have the 20 inch wheels. It is strange to have it resonate into the cab like it does.

I know a GM engineer who works on sound issues and I hope to find a chance to discuss it with him.

H1ghlndr · August 4, 2016

I am going down the route of the fender liner. Very wobbly and lots of pockets. I put in a piece of pipe insulation to try to stabilize. It did reduce quit a bit. I think the ticket will be to:

- Remove fender liner and coat back with dynamat or similar to reduce resonance and stiffen

- Put dynamat or similar on all areas of firewall not covered (a lot btw, especially in cavity between liner and firewall right)

Thoughts?

Bob

lmdnmmw · August 4, 2016

I have the same issue with noise at 30-40 mph with Goodyear Duratracs. I have my truck at the dealer now and we have replaced the tire, rotated the tires and it's not that noticeable unless you are in the driver seat. They don't know what else to do other then blame the tires.

I have a 2016 HD Denali with 3300 miles on it.

lmdnmmw · August 4, 2016

So the dealer said, they have less equipment on the driver side of the truck which helps with sound deadening. It looks like I'm going with Dynamat.

Dynamat - Xtreme 18" x 32" Sound-Dampening Sheets 36 sq. ft.

Wanna2500 · August 4, 2016

Thanks very much for keeping us posted. It will be very helpful to see if you get it resolved.

In case in might help diagnose the issue, below is a summary of my "study" of my issue

The noise is there all the way down to about 18 MPH

It is less audible in the mid to high seventies because the engine is making more noise then

It goes away completely on very nice blacktop road surface

It has a sound similar to a failing wheel bearing

It is is addition to the normal tire noise

I even shut the truck off going down hill and that had no effect

As mentioned, I have 20 inch wheels, Defender LTX MS2 tires, 4 wheel drive with the factory Ranchero shocks and the slightly larger factory sway bar. 2016 Denali 2500 Duramax - 3000 miles.

I wonder if anyone who has the issue has driven a truck that does not have it. it would be interesting to see if there are equipment or other issues which distinguish between trucks. I am getting the sense that most have it, but for some customers the noise seems normal.

i will say that overall the truck is very quite which is one of the reasons the noise is as noticeable and irritating as it is.

George C · August 6, 2016

I am going down the route of the fender liner. Very wobbly and lots of pockets. I put in a piece of pipe insulation to try to stabilize. It did reduce quit a bit. I think the ticket will be to:

- Remove fender liner and coat back with dynamat or similar to reduce resonance and stiffen

- Put dynamat or similar on all areas of firewall not covered (a lot btw, especially in cavity between liner and firewall right)

Thoughts?

Bob

My concern would be trapping ice and salt if you live in the northern states.

Wanna2500 · August 6, 2016

Based on your post, I did some research on the Dynamat and its reviews are amazing. Your installation plan seems to make sense as well.

H1ghlndr · August 8, 2016

Hey, Gang:

Here is an interesting page I found while doing research on best attack. Notice wheel liners....http://www.myturbodiesel.com/wiki/soundproof-car-diy-to-reduce-noise/

Also, just curious. Are well all GMC owners complaining about this? I ask, because the wheel liners are different for silverado than sierra. Silverado uses 18 bolts, and Sierra uses 13 as it relies on the wheel arch moldings to keep wheel liners in place, but they don't secure them.

Other thoughts from folks?

Cheers,

Bob

Wanna2500 · August 9, 2016

Bob,

I have driven a Silverado LTZ which did have the noise.

Based on your plan, I was looking at my truck and there is a significant section of uninsulated metal on the driver's side of the firewall. Interestingly, there is significant coverage of the firewall but for the section right behind the wheel.

I think your plan of of insulation would work well. I hope to chat with my GM friend next week to see what his assessment is.

John

H1ghlndr · August 9, 2016

Thanks, John.

It is bizarre that there is no insulation there when there is some right next to that cavity. I am ordering a new inner liner tomorrow and the insulation stuff. I am thinking of having local Rhino liner guy do the inside (facing engine) of the liner first to stiffen and then use a dynamat like product on top of that. I will also put that into the cavity you mention on the firewall. I am on vacation until 18th, so probably won't get to it until that weekend (20th).

Please keep us posted if you find anything out from your GM friend.

Maybe someone will try this before hand.

Cheers,

Bob

dab5577 · August 9, 2016

I've noticed this on my truck when slowing down from ~45 until i get below 20 or so. Curious what you guys find. I didn't notice it until I installed DuraTrac's back in December....but I might have just not been paying attention.