New member here, but long time lurker.

I have a 95 Z28 M6 with a little over 100k. The rear end is stock with 4:10's which were installed a couple of years ago. I raced a few times with some BFG DR's and I know the rear end took a beating those days since I was launching between 3500-4000 rpm.

Last summer I noticed some issues with the limited slip. If I am in a straight line and I "light 'em up", both wheels spin. If I want to whip it around, it will go into one wheel peel and not want to whip like a Z28 should. Yes, I like to drive my car and have fun fom time to time. I have also noticed a build up of grease in the right rear wheel. I was told by someone at a local shop that my I probably had a bad axle bearing or seal go bad? I don't remember exactly. I plan on doing some more upgrades in addition to some minor bolt ons I have right now, and I intend on switching over to a 12 bolt when I get the funds; but what could be causing the issue at hand? I'm hoping I can just swap out the diff at the most and call it a day for now. Do I need a new axle, or axles? Any help would be greatly appreciated, I am not real keen in the drivetrain area of cars yet.

I will make a sig when I have more time since right now I am at work.