Hello! I'm new here and looking for advice! Has a rebuilt 70'* GM 10 bolt rear end, gears, stock yes everything is new and set up professionally. BUT, it makes a whining sound when it rolls, when I give a tiny bit of throttle it becomes quiet. The workshop that did the work assembled and disassembled 5-6 times to get it optimal but never got rid of the whining....tired and annoyed listening to it but don't know what to try next...Anyone have any suggestions reason for this?

Sounds like the pinion bearing is singing. It really shouldn't so that at all, but if it is still doing it after like ten miles then they need to fix it.

I know you said everything is new, but to diagnose further I have to check:

- All new bearings?
- All new races?
- All new gears?
- All new carrier?
- All new differential gears and/or limited slip?

What were the manufacturers of each?

Did they check the axle for alignment?

Is this an axle and/or driveline shop or a normal mechanic?

First I want to apologize for my grammar, I use google translate😅 Thank you very much for your answer to my question! What is strange is that before I had the axle rebuilt, there was the same whining sound in it, only much louder. Yes, all the bearings, races, ring gear, pinion are new. The carrier was reused and it is limited slip. The work was done in a workshop where the owner specializes in these axles, and has worked with it all his life. The axle was inspected, and no cause for the whining was found. That was also why the innards were assembled-disassembled-assembled out and in 5-6 times, special shims were made and everything possible was tried, but without success🙈 The problem is that this workshop is 10 hours away from me, so going back there is out of the question🙈

Your Google Translate English is coming out well!

Did they check the axle for alignment?

Did they install a new crush washer or re-use the old one?

Not sure if I understand what you mean by alignment? Are you thinking about the whole axle or the inside? (I'm not very good at this, you understand). But the crush washer/sleeve was not reused, a new one was fitted. Could the preload have been loosened since the whining has increased a bit? might it be an idea to try re-tightening the pinion nuts a little carefully?

I mean the whole thing. It could be bent I suppose. We're running out of other things to look at.

That'* a possibility. Maybe you can tighten slightly then see what happens . . . ? Really this should be fixed by using some compound and seeing where the gears mesh. Has your guy been using compound and adjusting based on that?

when it comes to alignment, I don't know, but I almost want to believe it since everything was checked🤔 I can try to tighten the pinion nut a little, is there any torque specs this should have with gears and shafts mounted on it, I know it'* torque specs for the nut without gears and axles and such fitted.

Yes, some yellow compound was used to secure the contact point between the ring gear and the pinion.

If you tighten the nut and it makes the problem worse, you'll need to use a new crush washer after loosening it.

It sounds to me like an improper set-up. If you've driven it over about 100 miles, you might never get the noise out of that gear set . I have also seen poor quality aftermarket gear sets (ring and pinion) cause whining issues. You might want to consider bringing it back to the rebuilder. Not a lot of help, just an opinion.