Beans

I just purchased a 93 GC, 4.0, AT In checking the axle for the gearing the only tag on it states use Limited Differential Fluid only.

So Do I assume that I have .355 gears with a limit slip rearend????

dirtmod0

the gear tag would be attached to the cover bolts. I am assuming someone maybe lost this tag if its not there. but most likely its a 3.55 gear and not sure on the limited slip.

Gee oh Dee

If it says limited slip I would assume its limited slip. At least if you change the fluid use the stuff for limited slip.

BMac329

I would go to a dealer to get a build sheet printed up, Mine showed up with 3.55s. The LSD you will be able to see when you open it up, look on either side of the case and see if there are little shim things (clutches), this will tell you if you have a LSD.
I wouldn't trust tags unless you can be sure it hasn't been fiddled with before.

jeep bandit

Jack up the rear end so neither tires are on the ground. Then spin one tire. If the other tire spins the other direction from the point of view of the first tire it's an open diff. If it spins in the same direction, you have an LSD.