I have a 1989 Cherokee 4.0 motor with approx. 175,000 miles on it. It has been giving me problems starting. When I turn the ignition key, the starter wont even turn. I have tried pushing the jeep back and forth, and slamming the shifter into park. I tried to arc the starter by touching a long screw driver to the contacts on the starter and all that would happen is the motor in the starter would turn without engaging to the engine. Frustrated, I replaced the starter with a new one and the problem is still there. There is plenty of battery, just not starting. Has anyone else had this issue? If so, is there any way to fix this without taking it in to a shop? It's driving me crazy, I want to push it over a cliff!! Any advice would be greatly appreciated.

when you turn the key can you here the start spinning (not the engine but the starter itself)?

Have you checked the teeth on the FLYWHEEL? You may have some broken teeth and this is why the starter is not engaging/cranking the engine.

Try turning the crankshaft (engine) by hand with a ratchet and socket on the center bolt of the crankshaft pulley about half a turn then try to start the jeep.