Rear End Thump

[PaulieK]

O.K. Here is the deal, I have a 2005 Silverado 1500HD CC 6.0 with Quadrasteer. The problem is this. Whenever I back up or go forward over uneven surfaces and turning the steering wheel I hear what sounds like a midget with a hammer under the truck tapping the floor. It is a thumping sound like a dull banging once or twice. Where it really does this badly is when I pull up hill past my driveway and put the truck in reverse to back into my driveway. As I move rearward downhill and cut the steering wheel I hear it and it seems to be coming from the rear of the truck although I can sometimes feel it in the floor under my feet. I see when I did a search about rear leef springs slapping but it would appear that is for 2002 to 2004 trucks. Oh yeah, This makes this sound whether I am in 4 wheel steer or in 2 wheel steer mode.

[Mark_in_Tulsa]

Whenever I back up or go forward over uneven surfaces and turning the steering wheel I hear what sounds like a midget with a hammer under the truck tapping the floor.  

 

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I'm telling you right now it's a garden gnome.

 

 

But does it make the sound once, or is multiple times.

[PaulieK]

Whenever I back up or go forward over uneven surfaces and turning the steering wheel I hear what sounds like a midget with a hammer under the truck tapping the floor.  

 

<{POST_SNAPBACK}>

 

 

 

 

I'm telling you right now it's a garden gnome.

 

 

But does it make the sound once, or is multiple times.

 

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One or two quick thumps

[ChevyTech007]

Are you sure its not the steering shaft? I have seen torsion bar bushings worn out cause this. Here is a bulletin that might apply.

 

Subject: Pop/Clunk/Click Noise on Right or Left Turns - keywords body floor front mount pan steer suspension #PIT3118K - (02/24/2006)

 

 

 

Models: 2002-2006 Cadillac Escalade Models

 

2002-2006 Chevrolet Avalanche

 

1999-2006 Chevrolet Silverado

 

2000-2006 Chevrolet Suburban, Tahoe

 

1999-2006 GMC Sierra

 

2000-2006 GMC Yukon Models

 

 

 

 

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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

 

Condition/Concern:

Owners may comment on a pop, clunk or thump type noise when turning left or right. This noise may be heard and/or felt at either the drivers or passenger floor pan area.

 

Recommendation/Instructions:

Note: Body mounts are number as below and depending on the body configuration the number of mounts will vary. Example, a Suburban will use all 12 mounts listed below and a Regular Cab Truck will only use the first 6 listed below.

 

At Rad Support in front of vehicle are the "Front End Sheet Metal (FESM) Body Mounts" Left Hand & Right Hand.

At the A-Pillar of the body are the "#1 Body Mounts" Left Hand & Right Hand.

At the B-Pillar of the body are the "#2 Body Mounts" Left Hand & Right Hand.

At the C-Pillar of the body are the "#3 Body Mounts" Left Hand & Right Hand.

At the Quarter Panel wheel opening are the "#4 Body Mounts" Left Hand & Right Hand.

At the tailgate in the rear are the "#5 Body Mounts" Left Hand & Right Hand.

 

This noise may be caused by the #1 body mount. To correct this concern install 4 of the following insulators:

 

Install two insulators, P/N 15053229 on the bottom of each #1 body mount between the body mount and frame. Before these insulators can be installed, they need to be trimmed to fit. The inner diameter will need to be cut to 2 inches (52 mm) and the outer diameter to 3 1/8 inches (80 mm).

Tighten the body mount bolts to 85 N·m (63 lb ft).

Test drive the vehicle to verify the repair.

Important: While the #1 body mounts are removed check the underbody area that interfaces with the top of the body mount for excess build-up of E-Coat Primer or other foreign material. If the surface is not smooth use a 90 degree die grinder, or equivalent to remove the excessive build-up. Apply an anti-corrosion protection to the bare surface as necessary to prevent rusting and re-assemble.

 

Note: During the warranty submittal, please identify the location of the body mount that was serviced per the location list documented above.

 

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

[PaulieK]

O.K. Here is the deal, The truck went into the dealer yesterday. I had taken the service manager for a ride and he heard the noise I was describing. Well I just got off the phone with him and this is where we are at so far. They have retorqued and lubed the entire chassis and just for chits an giggles replaced the intermeadiate steering shaft. So they will give me a call in a few hours and let me know if the sound is now gone or if they will be keeping it another day to run diagnostics on the chassis. I guess they can rig it up to listen for noise etc. I personally thought it was the rear leaf springs but I am not a mechanic so hopefully it was just a loose mount or somthing.

[Norseman]

O.K. Here is the deal, The truck went into the dealer yesterday. I had taken the service manager for a ride and he heard the noise I was describing. Well I just got off the phone with him and this is where we are at  so far. They have retorqued and lubed the entire chassis and just for chits an giggles replaced the intermeadiate steering shaft. So they will give me a call in a few hours and let me know if the sound is now gone or if they will be keeping it another day to run diagnostics on the chassis. I guess they can rig it up to listen for noise etc. I personally thought it was the rear leaf springs but I am not a mechanic so hopefully it was just a loose mount or somthing.

 

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Ok, what was it? Please tell.

[PaulieK]

O.K. Here is the deal, The truck went into the dealer yesterday. I had taken the service manager for a ride and he heard the noise I was describing. Well I just got off the phone with him and this is where we are at  so far. They have retorqued and lubed the entire chassis and just for chits an giggles replaced the intermeadiate steering shaft. So they will give me a call in a few hours and let me know if the sound is now gone or if they will be keeping it another day to run diagnostics on the chassis. I guess they can rig it up to listen for noise etc. I personally thought it was the rear leaf springs but I am not a mechanic so hopefully it was just a loose mount or somthing.

 

<{POST_SNAPBACK}>

 

 

 

Ok, what was it? Please tell.

 

<{POST_SNAPBACK}>

 

 

 

 

Well this is what they found. When going over uneven surfaces the rear leef springs were making noise. The retorqued a greased the springs/insulators as well as the rest of the suspension and chassis. The noise is now GONE. Also while they were at it the replaced the intermediate steering shaft. So hopefully the noise wont come back at least for a while.