Differential issue...

[| 1990 ZR-1 |]

Well Gentlemen, here I am again seeking help with the beast. I've had a great time for the past 3 months with the car since I repalced all the injectors, brakes, and replaced/fixed the FX3 system. Now I have an issue with the rear diff. The car is MY 90 with 34k original miles.

Two weeks ago, I noticed the driver rear wheel visually looked out of allignment. Upon closer inspection, it had a pretty big negative camber, and the toe was pointing in. A couple of days prior, I hauled about 300lbs in the trunk area, which I didn't think was a big deal, but it sure enough caused some kind of damage. The car drove fine with the exception of very slight vibration at about 40 mph. At first I thought maybe one of the busings wore off or expolded, or some suspenssion part either broke or bent, but after jacking the car up and inspecting all the components underneath, I didn't see anything out of ordinary. I dropped the car off with my local mecahnic, and he said that something in the differential broke and is causing the wheel to get out of allighment. He said he would not take it apart and suggested we replace the whole rear diff, which looks like an expensive option.

My questions are:
Has anyone else experienced anythign like this and could tell me which part would be a suspect? I searched the tech forum, but didnt' see anything.

Should I take the car from my macahnic and take the diff appart to see if i can fix it?

I've never removed diffs before, but am pretty handy. How complicated is it, and would I need any special tools? I do have the service manual that I will reference to, but if anyone has step by step instructions they could reference, I'd appreciate it.

Last but not least, I keep reading about the 4.10 gear upgrade. How envolved and costly is this upgrade? If it's too much money, I'd rather just replace the broken part, and put her back together.

As always, thanks in advance!


-Gary