I have a 95 Z28, automatic tranny. It is mostly stock. Recently I noticed I had a differential leak. I replaced the front and rear seals in the diff. and replaced the fluid with Royal Purple gear oil. I have probably put 250-300 miles on it since doing this. I noticed today while driving around that when I am turning at a slow speed(2-8mph) I can hear a barely audible whine coming from the rear end. At first I thought it was the power steering but the more I listened and played around with it I am positive it is coming from the rear end. Not sure if it is the diff.... maybe bearings, I don't know. Anybody have a clue what the problem could be? I have also noticed after installing the Royal Purple that the rear end shudders a bit if I get on it enough to break traction. Just before the tires start spinning you can feal the rear kind shudder a bit.

 

If you have aftermaket gears in the rear it could cause it to wine if there not instaled properly. Maybe you low on fluid.

 

No everything is pretty much stock. And this whining didn't start until yesterday. It drives fine. No problems seemingly. Just the noise. When I put the nut back on the front after changing the front seal, I didn't have the proper tools to check the torque on it so I just got it as close as possible when tightening it. It is pretty dog-on close to original but I wander if over or undertorqueing it could cause it to whine. Even though it didn't start until like 250-300miles later... I talked to another guy that sayed I shouldn't have used Royal Purple in a Chevy. He said it was specifically designed to use a certain viscosity gear oil. But the Royal Purple bottle clearly indicates that it meets the viscosity needs. Let me know what you all think.

 

did you change the crush sleeve on the pinion bearing or did you reuse the old one? yes, under or overtighteningwould cause it to whine. does it happen most noticeably when you let off the accelerator and let it coast down? downshift manually? if so, then your gears aren't meshed properly (set up problem) if not, and it happens only in a turn, then it's likely a problem with your LSD carrier. the shuddering makes me think the latter.