4.0 Engine question

Hey Im new to the site. I just bought a 91 4.0 5speed cherokee. the jeeps got 215,000 on it and the guy i bought it from said it has a rebuilt motor 50,000 miles ago. and I think hes full of it. the motor knocks when ur at a steady speed right before i shift. the rear main or oil pan gasket leaks. (one of the two i cant tell. its leaking oil down the front of the tranny) Now my question is should I rebuild or replace the motor?? I am not sure on which would be the best bang for my buck. Are the remanufactered motors any good to buy?? so hope i can get some feedback from you guys. Thanks a bunch.

Take the oil pan off to replace the seal/s and check if there is excess play in the rod bearings. They will move side to side a little but should not be sloppy. Then take the main caps off one at a time and see if the bearings are scored. If the bearings look good then you are probably O.K. These engines normally make clicking sounds from the valve train but if it is knocking then you may have issues.

if its not a daily driver, i say pull it rebuild it maybe even stroke it