will a driveshaft off a grand cherokee fit on my 96 xj?

 

All depends on the driveline that was in the Grand. Measure the old and measure the new. If the length is the same you should be good.

 

Front or rear?

 

okay...rear

 

4x4 XJs came with about 8 different lengths and grands have 2 or 3 so you'll need to measure. I ask front or rear because the front on an XJ is a little longer and some ZJs use a cv instead of a u-joint at the axle.