I just opened up my rear diff cover today. I've only had the car for a few weeks, and I'm trying to figure it all out so please bear with me. I've figured out that it's a 4.10 ratio with posi. These are NOT the gears that came on my car based on the rpo codes. If anyone can help me out with identifying this it'd be a huge help... Also, I can't pry open that little cover.... How can I get it open?

 

No It is not stock none of them came with 4 10 gears. Looks like a torsen LSD to me. I would seal it up and lube it up and run as is.

 

Detroit Locker. Why do you want to take it apart?

 

Thank you! I bought this car in rough shape. The previous owner mentioned that the passenger rear drum brake had seized so the owner before him cut off the old brake entirely, including the backing plate. I figure I should just convert to discs in the back no, so I need to get the axles out to mount a new caliper bracket. And even if I were sticking with drums, I'd have to remove the axle to put in the new backing plate for it. I'll have to fool around with it to see if I can just get the axles out somehow.
Here's a pic of what I was left:

Passenger Rear Brake - Was cut off by previous owner.

 

Notice the bolts around the right end of the differential. The bolt that is in line with what you are calling a plate is what holds it in. This plate goes deep into the differential and separates the axles. When you remove it you will be able to push the axles in and remove the c clips.

 

This bolt, correct?

 

Yes, that's it.

 

Thank you big gear head! I got my axles pulled out and now I'll be looking at which disc brakes to use. One of the previous owners converted this car to 28 spline axles too, glad I waited on ordering the new axles.

 

That's good news.