5.2 ZJ is rated to pull 6500 lbs. I've pulled 6300 with my niner, and I wouldn't really recommend it. It's not terrible, but you better have damn good trailer brakes, and you do get pushed around a good bit.
As far as trannies, a 93 - 95 5.2 has a 46RH, 96 - 98 has a 44RE. Both are good trannies if taken care of (keep fluid fresh, add a big cooler, shift kit doesn't hurt either). And both can be built very strong if desired.