issue Popping noise from under the bed area?

[bobbyd]

Same noise here - Sierra AT w/Z71 (Rancho Shocks). Finally took it in to the dealer. They had it for two days - said it was a loose piece of plastic on one of the shocks. When asked why it only happened in V4 mode, or when switching from V4->V8 or vice versa, they said it was the resonance of the exhaust causing the plastic on the shocks to vibrate and make the noise. Two new shocks later, same damn noise.

I'll be bringing it back next week.

[GMCustomerService]

My noise is a rattle under the bed when I close the rear door and that is when I hear it. I think it is the skid plate rattling that protects the gas tank. I plan to take it to the dealer to get it fixed.

 

Hey Jacksfan98,

 

Let us know how your dealer visit goes! If you would like any assistance setting it up we are here and happy to help.

 

Jonathan A. (Assisting Jennifer)

GM Customer Care

[Mattmars]

Is there any way this sound could be caused by the adaptive valve in the exhaust pipe? I've noticed it too when making turns from a stop.

[nspec]

As I try to pin this down, I'm starting to h

[nspec]

As I try to pin this down, I'm starting to think it's only happening when damp outside. Leads me to believe it is a rubber bushing somewhere.. shock or spring hanger. It's not an exhaust hanger. Definitely related to suspension in some way. Mostly happens turning left when the right rear compresses. Cold and dry, no noise. Damp or rain - noise. Don't think it's mechanical.

 

Thoughts?

[klrrdr]

Sitting in stop and go traffic today, after driving about 60 miles. Every time I started to move and went a few car lengths and stopped there was the loud thunk. as mentioned before it sounded like a bowling ball hitting the tail gate then the front of the bed. put up with this crap for about 8 miles. Please post if you ever find out what this is,only 550 miles on AT SLT

[Charlieo132]

Had the back shocks replaced and haven't had the problem hasn't happened since.

 

Ment the problem hasn't happened since they were replaced.

[BringTheRain403]

Sitting in stop and go traffic today, after driving about 60 miles. Every time I started to move and went a few car lengths and stopped there was the loud thunk. as mentioned before it sounded like a bowling ball hitting the tail gate then the front of the bed. put up with this crap for about 8 miles. Please post if you ever find out what this is,only 550 miles on AT SLT

 

That sounds like someone screwed up setting the backlash in the rear end...

[Chris]

Could be another slip yolk issue. The past couple gens had that problem

[tbare54]

Just a thought, everyone having the thump noise under the bed, could you post the size of your fuel tank. Mine is doing it at starts and stops, like pulling in or backing out of garage or maybe at a traffic lights. I've got the 35 gallon fuel tank and I'm pretty sure it is the movement of the fuel back and forward that I am hearing and feeling. GM cut corners and forgot to put baffles in the large tank, now they are playing stupid, like they hear the noise and feel it, but no remedy. My Silverado has spent 8 hours at a dealership in Arizona and 4 hours at a dealership in Indiana and all the can say is GM doesn't have a fix, I guess my next action well be to contact the NHTSA, maybe they will be concerned with a possible fuel tank problem.

Edited December 14, 2013 by tbare54

[GMC-AT]

Tbare54,

 

You make a great point.. I was just thinking about this the other day. Seems like the issue is when going over rough roads. .....dirt roads... low speed... where the fuel can move around. Seems more noticeable when the tank is FULL.

 

I have a standard 25 or 28 gallon tank..not sure the exact... but it's the standard tank size. But it's interesting that you mention this....

[GMCustomerService]

Hey there,

 

If anybody would like us to assist in getting this concern resolved or touch base with their dealer feel free to contact us via PM. In order for us to set up a case would you please provide your full name, contact information, VIN, current mileage, and the involved dealership?

Sincerely,

 

Jonathan A. (Assisting Jennifer)

GM Customer Care

[Buckwild]

I have the same noise at times too from right side under box with the Rancho shocks. The shock seems more likely the issue as it seems to happen on rougher roads which will make the suspension move quicker. I doubt it's fuel sloshing from having no baffles in tank, if there were no baffles the fuel would move away from the pickup tube and the engine would die every time you accel or brake.

[tbare54]

Mine doesn't have rancho shocks, most modern fuel tanks have the fuel pump built into the tank itself, at the bottom of the tank. Not sure there is even a pickup tube because the pump is emerged in the fuel to keep them cool.

[dredd]

2014 5.3 z71 4x4 1300 miles 3.08 gear ratio

 

Has anyone had an issue with a loud popping noise from under the bed or around the back wheels area? This is most noticable in the morning and when you are accelerating from a stop around 5 - 10 mph.

 

Dropped the truck off this morning but wanted to see if anyone else had the issue in case they come back and say they can't replicate or find the problem.

 

I have the same noise, and got on the forum today to see if I could find a thread where others are having the same issue. I have a 2014 GMC AT 3,654 miles. I only notice in the morning when I back out of my driveway, and then leaving next 2 stop signs accelerating. I just went outside and bounced on my hitch and it made the noise once then nothing. I believe my problem will be the shocks. Even my wife new it was something in the suspension when she heard it, but take it to the dealer and they can't duplicate.

 

Bad batch of Rancho shocks? or just POS?