Aisin 8980 11

Hi Guys, my question is that I have a 1993 Cherokee 2wd with a 4.0 engine. Is has an automatic transmission. So far, I have found that it is an Aisin 8980 11 model. The guy that had it before me pulled a camper that was way to big for it and now 1st gear slips but I can still get around if I baby it. Now it has developed a vibration at highway speeds and am sure its putting a big strain on the universal joint. I have tried to change the rear seal twice as fluid is leaking from where the drive shaft enters the rear. I did notice that there is quite the amount of play where the drive shaft goes in and am pretty sure the (output shaft bearing??) is shot. Any info on transmission compatibility would be appreciated.. Thanks