magician

I've searched and read all I could find here about the noise some Tahoes are having when going over speed bumps and such. I have the same problem but so far from what I've been able to find out is, mine is coming from both sides of the axle housing and seems to be cuased by some play or wear in that unit???

I've read where others have had the drive shaft yoke lubed but that seems like a different solution to a different problem altogether???

The noise I get happens when the suspension unloads and rebounds. I am able to duplicate it by standing on the runnning board and vigorously rocking the truck. When I got it up in the air and removed a wheel I could see some movement in the axle side to side. This movement cuases a grinding sound when the axle studs grind against the brake rotor. I dont know of a way to stop this, any idea's?

Some rotors are held in place with one of those push on type clips but this truck didnt have any when I got it...

in2pro

What year model?
2x or 4x?
The sway bar bushings can squeak and clunk after a while
the calipers may need to have the guides cleaned and lubricated
check that the lug nuts are all properly torqued
check the shock tubes for damage as the may be rubbing

magician

in2.
Sorry, its an 07, LT 2wd. I had the rotors turned a couple weekes ago after they failed run-out checks. I've heard no noise coming from the bushings, calipers or the shocks. I did find the wheels were waaaaay to tight but I dont think that would cause the grinding sound I hear?? I have taken the spare tire down and eliminated that as a cause.
Like I said, it seems like the rotors are grinding against the smooth part of the axle studs. I can make it do it with or without the wheels on the truck. I just dont know if this can be fixed or not? Some things you have to learn to live with I guess??

73shark

First the push-on retainers on the rotors are for the factory. They keep the rotors from falling off on the assy line before the wheels are mounted.

With the wheels mounted, there should be no relative motion between the rotors and the studs. If you found the lug nuts over-tightened, then that could have been a cause of your warped rotors.

Can you make the noise by rotating the wheels by hand? Or is it just w/ suspension movement\?

magician

73shark

There is motion with or without the wheels mounted but it only occurs when the suspension rebounds or when the weight is off suspension for a brief moment. Also, when I remove the wheel and tire I can move the rotor in and out enough to make the sound. Then again with the tire off, I should be able to do this??
Seems like a lot of wear might have caused the clips in the rear diff to be somewhat loose and that could be causing the axles to be moving slightly in and out of the housing. I'm not familiar with GM rear diffs so I dont know if there is some type of holder or keeper that keeps the axles inside the housing??
Either way, unless I change the rear out this may be something I just have to live with if I cant find a way to fix this.

After getting into the truck again for a while today it seems like I have a shock problem on one side. Its amazing how sounds transfer around under this thing... Hopefully this will fix the noise??

73shark

So are you saying the entire axle is moving in and out?

magician

The problem ended up being driy/worn bushings in the area of the rear suspension trailing arms. Once they were off and replaced the problem was gone. Anyone having this same issue should look there since there are four links and bushings at both ends of each.

Thanx for all the input and questions. It all helped me get to the right spot to get rid of this.

magician

Okay, now I stand corrected. There was no issue with the shocks or the bushings there and on the upper and lower rear control arms. I did find a loose brake dust shield that I dont know how to correct.
So far this noise goes away whenever I put the truck on the lift but comes back in a few days of normal driving? I can make the truck make this noise by vigorously rocking the truck side to side while standing on the passenger running board. Repeatedly doing this has me believing that I do have a problem in the rear diff after all. It seems like there is movement of both axles laterally with the wheels on and the truck on the ground of about 1/16th - 1/8th of an inch? I cant get it to do this by pushing side to side on the truck either? It might be moving more except for the brake caliper??

I dont know what else to do except tear into the rear diff and see if the C-clips are worn excessively and might be causing this noise? Anyone else have a better suggestion? This is getting to be quite a pain,,,