Boomy sound from rear

[nuclearbeef]

Seems the rear of the truck is very "boomy" going over rough pavement.
Even expansion joints in the concrete cause a "boom" in the passenger compartment.

Has anyone found the source of the sound or a fix?
My Troopy was very similar. A little insulation on the ceiling and floor knocks 90% of the sound down.

Insulated mat for the cargo space?
Or is it more roof? Dynamat under the headliner?

 

[Norb-TX]

You're right about the lack of insulation, whenever I use the big horn, it sounds like its mounted inside the cabin!

 

[Texas Grenadier]

I'm getting a drawer system for mine. Hopeful that it will quiet mine a little too.

 

[Greg]

I put this in as i will be removing the standard flooring mat when i build the drawers. This will give the drawers something to sit on.
Until the drawers are in the standard floor mat goes over it no worries.
It does seem to reduce the noise as it is designed to lessen panel vibration of which there seems to be a bit on the boot floor... give it a tap some time with the mat removed.

 

[nuclearbeef]

Maybe something like this would help.

 

[anand]

My plan will be 50-80% coverage CLD over everything, then 3M Thinsulate on the doors/sides/roof and 3M Minicell + 3M TAI on the floor... Not sound related, but also a layer of 3M Low-E between the Thinsulate and headliner

 

[Greg]

Whilst i would love to add more (I have gone crazy on my previous cars) I am mindful of adding extra unnecessary weight. This is just to compensate for the removal of the boot mat.
Just by getting in the driver's seat I add 115kg...

 

[Jiman01]

View attachment 7847155

Maybe something like this would help.

Does it come with a years supply of chloroform or ether?

 

[AWo]

I put this in as i will be removing the standard flooring mat when i build the drawers. This will give the drawers something to sit on.
Until the drawers are in the standard floor mat goes over it no worries.
It does seem to reduce the noise as it is designed to lessen panel vibration of which there seems to be a bit on the boot floor... give it a tap some time with the mat removed.
View attachment 7847143

Is that something like alubutyl? Glued in? Like black tar?
Hopefully not....you'll never get this out again without a lot of work, dirt, sweat and swearing. I would never use such stuff.

AWo

 

[donnygreygrenadier]

Seems the rear of the truck is very "boomy" going over rough pavement.
Even expansion joints in the concrete cause a "boom" in the passenger compartment.

Has anyone found the source of the sound or a fix?
My Troopy was very similar. A little insulation on the ceiling and floor knocks 90% of the sound down.

Insulated mat for the cargo space?
Or is it more roof? Dynamat under the headliner?

I found reducing the tire pressure helps a little. Recently, tire pressures went up (short term warm spell) and the boomy noise increased). Tire pressures were up to 45F & 50R (cold). At delivery I had the dealer set them 5psi lower - yesterday I reduced down to 40F & 45R.

 

[grenexplorer]

I found reducing the tire pressure helps a little. Recently, tire pressures went up (short term warm spell) and the boomy noise increased). Tire pressures were up to 45F & 50R (cold). At delivery I had the dealer set them 5psi lower - yesterday I reduced down to 40F & 45R.

Take them down even more....

I was at that pressure rolling out of the dealer and drove 4 hours home...wasn't the handling and sound I was hoping for. Dropped it to 39psi the next day...its perfect. I think some folks were even running 37 F/R.

 

[bikesandguitars]

I’ve noticed my steel wheels are quieter than my wife’s alloys. Also, I have a TM with a second battery. My wife has the FM that is somewhat hollow under the seat. I may put a piece of foam under the seat and see if helps. But I haven’t found either to be excessively noisy - but I am looking forward to a fitted weather mat in the rear. I’m bungeying everything down in milk crates for the time being.

 

[shiv.nandak]

So i have driven 4 other grenadiers with K02 tires and have not heard that noise. Meanwhile my grenadier with full sound proofing in the trunk, wheel wells, doors and floor still has the boom. I have also tried different tires (not k02) and the noise is still there. I have a very early US production model, i wonder if Ineos has made improvements in trucks that were produced later.

 

[DaneJa]

So i have driven 4 other grenadiers with K02 tires and have not heard that noise. Meanwhile my grenadier with full sound proofing in the trunk, wheel wells, doors and floor still has the boom. I have also tried different tires (not k02) and the noise is still there. I have a very early US production model, i wonder if Ineos has made improvements in trucks that were produced later.

It was definitely present in my '25, which is why it just got full sound deadening. I won't be able to evaluate how effective it was until next week.

 

[Jiman01]

So i have driven 4 other grenadiers with K02 tires and have not heard that noise. Meanwhile my grenadier with full sound proofing in the trunk, wheel wells, doors and floor still has the boom. I have also tried different tires (not k02) and the noise is still there. I have a very early US production model, i wonder if Ineos has made improvements in trucks that were produced later.

That's disappointing. Do you have anything in the back, ie drawer system or anything else that takes up volume in the space?

 

[shiv.nandak]

That's disappointing. Do you have anything in the back, ie drawer system or anything else that takes up volume in the space?

I do not, but i have noticed the noise significantly reduce when i am loaded with passengers and items in the trunk.

 

[shiv.nandak]

It was definitely present in my '25, which is why it just got full sound deadening. I won't be able to evaluate how effective it was until next week.

Do you have K02s?

 

[HereinDaRockies]

So i have driven 4 other grenadiers with K02 tires and have not heard that noise. Meanwhile my grenadier with full sound proofing in the trunk, wheel wells, doors and floor still has the boom. I have also tried different tires (not k02) and the noise is still there. I have a very early US production model, i wonder if Ineos has made improvements in trucks that were produced later.

The k02 grenadiers you drove, which has no boom, were they produced much later than your’s your hypothesis is later VINs have improvements to reduce the booming sound - but did you confirm the build dates, or did you only focus on the tire difference?

 

[HereinDaRockies]

Is that something like alubutyl? Glued in? Like black tar?
Hopefully not....you'll never get this out again without a lot of work, dirt, sweat and swearing. I would never use such stuff.

AWo

Yep it is.. I applied in mine as well.. don’t care.. won’t remove it ever again..

 

[AWo]

Yep it is.. I applied in mine as well.. don’t care.. won’t remove it ever again..

That's what I would fear.....taking it out again. I had Alubutyl on the roof of my 101 FWC. That was one of the worst, ugliest and longest works I've ever done to get rid of it...never again...bahhh...
Starting with a spatula do get the thick parts away, then ice blasting (which only works on a thin layer left) and as the last step removing the remainings with a very, very slow running grinding machine to absolutely not applying any heat. A liite bit of heat and the stuff starts to smear and glue and then the drama starts again...

There are other things available for dempening the sound, so you do not need Alubutyl anymore...




AWo