Hello all. I have had an '03 Electron Blue Z06 for about 6 months now. One item that bothers me that I have not been able to fix yet is the 'creaking' or 'popping' noise from the rear of the vehicle that occurs when driving at low speed (say 10 mph or lower) on / over a road surface that causes the suspension to twist. Like going down the small driveway curb at an angle. (which causes the chassis to twist). The noise occurs on a large variety surfaces when ever a slight twist of the chassis occurs.

I have determined the 'creaking' does not come from the front / rear suspension or the sway bar. Also checked the noise is not coming from the rear fasica rubbing on the crash absorption material.

Seems the 'creaking' is coming from relative motion between the chassis and the rear fiberglass tub which drops down directly beneath the rear hatch/trunk between the chassis rails . I have confirmed by lifting the rear of the vehicle on one side to hear the 'creaking' noise.

I cannot seem to find the precise source of the noise or how to remedy.

Has anyone had a similar noise and ideas for solution? Trying to determine of this noise is 'normal' or not before I pull apart the back of the car trying to find the root cause.

 

NOT your year model, but sounds like what you're describing. Check it out.
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Document ID# 1384476


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Creak, Popping Noise from Rear of Vehicle - bracket bump clunk frame joint knock loose noise pop rattle reinforcement support suspension #PI01369 - (Sep 18, 2003)
Creak, Popping Noise from Rear of Vehicle
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When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.

Condition/Concern:
The customer may complain of a creak or popping noise coming from the rear of the vehicle near the fuel tank area. The noise usually occurs when the chassis is twisted such as traveling over a speed bump in a diagonal direction and can be from the left or right side of the vehicle.

Recommendation/Instructions:
Remove the fuel tank. Looking up at the center of the vehicle, follow the tunnel coming downward. At the end of the tunnel, there is a metal piece that runs on a 45 degree angle from the center tunnel out to the main frame rail on each side of the vehicle. The metal piece is welded where it meets the frame rail. In this area, there is an additional vertical metal piece (gusset) between the chassis sheet metal and the metal piece previously mentioned. This gusset is welded to the frame on the inboard side. Poor weld penetration between this gusset and the frame rail could be the cause of the noise. Welding the gusset will correct this condition.

Please follow this diagnosis 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. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.

Models:
99, 00 Chevrolet Corvette

 

Thank you. I will look into this idea. I have found another location with poor weld penetration for a suspension mount - so maybe this service bulletin description is the cause for the creak / pop noise.

 

Cradle bolts are tight?

 

First place I'd look is the easy one. Check the sway bar end links and grease or replace the rubber bushings. I had the same creak, and I swapped the sway bar out with new rubber and it solved the problem. Try that first, as it's exceptionally easy.

 

Thanks All - for the ideas. I wanted to report back with the finding to date so - here is the current update.

1. Have not removed the fuel tanks yet to inspect the gussets and weld pentration - but, have spend some more time locating the creaking / popping noise and seems to be rearward of the fuel tanks - I am not sure what that is worth to me at the moment.

2. Checked the torque of the cradle bolts. All were loose including the front with the back quite loose. So I torqued all of the cradle nuts to proper torque per service manual. This did significantly helped and cut the annoyance in half - but did not eliminate. So now I am only half annoyed - therefore on the right track. I could actually hear the creaking when I was tightening the rear cradle passenger side front nut. Interesting.

3. Next will confirm if the rear sway bar is a player or not.