What is the correct gear oil I should put in my 96 xj? Also how much?

Thanks.

Manual transmission, differentials, or transfer case?

Sorry should've specified. Differential

get the heavy duty stuff down at advance auto they should be able to tell you. First time I changed my diff fluid, I realized that that is one of the greatest smells on earth.

Smells even better if you spill it all over your clothes. I could still smell it after running it through the washer twice. I want to say you'll need about 4 quarts to do both the front and rear. Can't recall the exact viscosity, but I think it was 75w-90.