I've been bothered by a clunking sound from the rear for a long time.
I know there are a lot of possibilities that can make such a sound, but here I want to exclude all the factors other than the diff and the axle shafts because I've already checked all the other things thoroughly.


So, is there anyone that successfully eliminated a clunking sound of the rear by replacing the diff and the axle shafts?

 

Clunk noises are usually caused by excessive tolerance. Those things, by themselves, won't generally make that kind of noise (they might but that would be quite rare; since they don't usually change size; but the act of changing them, specifically putting in new bearings and setting the preload on all of them properly and so on, usually makes a big improvement.

People also get used to a certain amount of random rumbling noise coming from the drive train, over a period of time. New axles can completely eliminate that.

And of course a new carrier gives you the opportunity to add posi, and replacing all the bearings requires stripping the whole thing down to the point that a gear change is easy.

So yeah, it's something you might want to consider doing.

 

I see that you have the stock limited slip differential, which would be the Auburn. The Auburn wears quicker than most other LSDs, and as they wear they greatly increase the clearance between the axle gears and the pinion gears. They also greatly increase the axle end play. Replacing the junk Auburn with a good LSD, like the Eaton Posi, Eaton Truetrac or Yukon Dura Grip will decrease the axle end play and the slop in the differential gears. You didn't say when you hear the clunking noise, so it could be something in the differential, axles, drive shaft or transmission causing it.

 

Thanks for your replies.


I wanted to make sure changing axles and a diff can stop the clunking sound because it costs relatively a lot to change them.


What is interesting to me though, is that the axle end play and the slop in gears don't necessary cause the clunking sound.
In my understanding, it is commom for the thirdgens to have this play and slop in the rear end.
Indeed, my camaro didn't have the clunking sound 6 months ago when there was already the same amount of play and slop in the rear.
Can tolerance in play change so rapidly?


Pursuing the cause of the sound, I found the following one day:
http://camaroforums.com/forum/82-92-...-camaro-55148/


He says he has a play up and down, not in and out.
If there is a possibility that a worn diff and axles can cause this new play, it makes sense to me that changing these can stop the sound.


What do you think?
BTW, my camaro makes the clunking sound only at a low speed, and only on a bumpy road. Other than that, everything is fine, no vibration and sound on a highway.

 

I swapped drive shafts, guess my old u joints were worn.. but yours could be anything, even a broken trans mount, bushing someplace, loose blown shocks, exhaust pipe banging, heat shield loose somewhere?? Make a video with the sound happening and post it.. I'm sure someone will have a better idea then..

 

Thanks for your reply.
But as I said at the beginning, I want to exclude all those possibilities here because I want this discussion to be focused on the diff and axles.

 

You still haven't said when the clunk occurs. Is it when you turn a corner, accelerate, slow down, take off?


Replacing the axles will not eliminate a clunking sound. The axles need to be replaced when the axle bearings go bad and eat into the axles.


As I understand it the transmission mount is what usually causes a clunking sound in these cars. It sounds like it's coming from the rear end, but it's not.

 

The clunk mainly occurs when turning a corner, and on a bumpy road, both only at a low speed.
It has nothing to do with accelrating, slowing down, or taking off.
The transmission mount is securely bolted.


If replacing the axles and diff doesn't play any role in fixing any clunking noise, then there is no point of replacing them.
But if there is a slightest possibility that replacing them can fix the problem, it's worth trying.
I just wonder if there is someone who experienced fixing this problem by replacing them...

 

Replacing the differential can fix some clunking noises, but not the axles. Like I said before, the Auburn wears out and creates excess clearance in the gears and allows the axles to move in and out.

The transmission mount might be bolted in well, but that isn't the problem. The mount tears in the rubber and causes the noise. This is a very common problem with these cars. It sounds like it's a rear end noise because of the torque arm.

 

I checked the transmission mount this weekend, and found no problem...


BTW, I want to know more about the Auburn diff.
I'm not knowledgeable about diffs, but considering its structure, is it possible that worn-out parts in the diff can cause play up and down, not just in and out, just like this:
http://camaroforums.com/forum/82-92-...-camaro-55148/


If it is possible, I think clunking on a bumpy road can explained by that.
In-out play will cause clunking when cornering, but I don't think it can cause clunking on a bumpy road.

 

Have you checked the bushings in the panhard bar? It seems to me like this might be an external problem, not something inside the rear end.

 

In order to exclude all the possibilities one by one, I'm going to replace the rear BMR LCA and BMR panhard bar with the stock ones this weekend.
They were replaced three years ago (about 21,000km use), but I'll replace them just in case.
The sway bar, the transmission mount, and the torque arm bush have already been re-attached.


Big gear head, so there is no possibility that the Auburn diff has up-down play, not just in-out one, in the axle, especially when no problem is found other than the clunk or click sound, right?

 

With normal wear there should not be any up and down movement in the differential. The axles gears and cones are seated in tapered holes and pushed in place by the springs, so they shouldn't me able to move around any. The pinion gears are light enough that you would never notice any movement in them. The differential is held in place by tapered roller bearings sitting in the bearing bores held in by the bearing caps, so no movement there with normal wear.

Have you checked the pinion to see if it is still tight? I is possible that you might get a little noise from the pinion if its loose. Sometimes the pinion nut will back off and allow the pinion to move around, or the pinion bearings could be bad and allow it to move.

 

I haven't check the pinion yet.
Can I check it by pushing in and out the propeller shaft?
Considering the fact that there is no noise or vibration coming from the rear at a high speed, though, I hope the bearings are fine.


So, with normal wear, there should not be any up and down movement in the diff.
As I said, there is no noise coming at a certain speed or more, so I assume everything is within normal wear.
Then, if the sound is still coming from the diff, is there any possiblity that the excessive, but normally worn axle shaft and diff side gear (splines) make any clunking sound due to its large clearance?
Likewise, the excessively worn axle shaft and the wheel bearing can make the sound on a bumpy road?