Big Jay E

2010 Grandsport. Developed a clunking sound in back when I go over speed bumps, etc. Any ideas?

Frankie15

Check this thread out:

https://www.corvetteforum.com/forums...ing-noise.html

It is likely one of three things:

Loose axle nuts
Need a rear end fluid change (What it ended up being for me)
Sway bar end links

ruxvette

Unless someone put in the wrong diff fluid it's not #2.
Hope for #1, but probably #3.

Not So Fast

Loose nuts for me No comment Bruze
if it occurs when you are turning then probably axle nuts are the culprit
NSF

Speed07

Replaced my end links and axle nuts soon after buying the car. Clunk gone.

LowRyter

change out the diff fluid with the correct fill. Check your book or service bulletin for correct fluid and additive.

Big Jay E

Are the axle nuts on the outside behind the wheels, or in the differential

User Omega

They are behind the wheels.

Some guys just remove the wheel center cap and tighten them with the car on the ground.

1-5/16 or 33mm socket will work just fine on them.

Some have reported that they come loose even at that spec so adding a bit of thread locker or a Nord washer is up to you.

Document ID# 2018487
2005 Chevrolet Corvette


--------------------------------------------------------------------------------


Subject: Tapping or Scraping Noise From Rear Wheel Area (Replace Wheel Drive Shaft Nut) #07-04-95-001 - (09/26/2007)



Models: 2005-2008 Cadillac XLR

2005-2008 Chevrolet Corvette




--------------------------------------------------------------------------------

Condition
Some customers may comment on a tapping or a scraping noise coming from the rear wheel area.

Cause
This condition may be due to the torque on the wheel drive shaft nut relaxing over time.

Correction
Replace the left and the right wheel drive shaft nut following the procedure below.

Remove the center cap from the rim.
Remove and discard the wheel drive shaft nut.
Apply LOCTITE™ 272, or equivalent, to the threads of the axle shaft.
Install the nut and tighten to the new specification.
Tighten
Tighten the nut to 215 N·m (160 lb ft).

Install the center cap to the rim.
Important: The vehicle should not be driven for 24 hours following the repair in order to allow the thread lock to cure.

Parts Information
Part Number
Description
Qty

10257766
Nut
2 (one per side)


Warranty Information
For vehicles repaired under warranty, use:

Labor Operation
Description
Labor Time

F9712*
Wheel Drive Shaft Nut - Replace
0.3 hr

*This is a unique labor operation for bulletin use only. It will not be published in the Labor Time Guide.




GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION


© Copyright General Motors Corporation. All Rights Reserved.

gliot1

I have an '06 I bought used that had the same issue. What I found that one of the sway bar bolts had come out.....while it sounds like a simple fix, the issue was that the "U" bracket holding the sway bar had bent and distorted a bit, making it difficult to align the new bolt to draw it in. Ultimately had to use a C clamp and some muscle to get the bolt started!!!!

Big Jay E

Does the 1 5/6 socket have to be a deep socket, or will a regular one work?

Not So Fast

I bought a 33mm socket and its pretty deep whether or not its needed As I remember it isn't but why not buy one anyway. I used the 160 lbs torque # but only took it to 150lbs, that's TIGHT
NSF

Cherokee Nation

I've read many time on here that GM dropped it down to 140 lbs??

Not So Fast

Yup

Big Jay E

Got the socket. My torque wrench doesn't go that high. I have a 24" breaker bar and was barely able to move the nuts so I don't think that was the clunking sound.

Frankie15

You still got two other things to check out. I am sure one of them is causing your issue. It's probably the end links if it only happens over speed bumps. Mine would occur during low speed turns in 1st and 2nd gear. Most noticeable in parking garages.

My end links and axle nuts were fine. For me, it was the diff fluid.

LowRyter

did you change the fluid? (confused)

Big Jay E

Have not changed the fluid. It is original. Will do that when I take it to Rydell. Local shop is going to put it on the rack tomorrow so we can chech out the end links.

Big Jay E

I have only heard the clunk one time when going over speed bumps with a pasanger in the seat. Doesn't do it when I am alone. What I will hear occasionally is what sounds like a body pop.

The top did that when I first got it and the dealer fixed it. When I hear it now, it is not coming from the top.

ruxvette

Doesn't sound to me like diff fluid. When it's up on the rack be sure to bang around on all the exhaust, look for contact spots, etc. However, if it's on a lift it will not be settled as it is on the ground.

LowRyter

the diff will click when making tight low speed turns.

It's probably not the reason for creaks and knocks going over speed bumps.