I got a 2000 cherokee classic with the 4.0. I replaced the motor last year and after 6 months flexplate cracked. Replaced it and it cracked again after 4 months. The last one only lasted about a month. I have talked to several people gotten several different ideas on what might be causing the problem.Getting ready to change again and this time I am going to change the torque converter as well. Does anyone have any other ideas on what might be happening? Could the crank shaft be a little shorter or longer maybe putting more stress on the flexplate? Any ideas would be appreciated.

 

If your thrust bearings are wore it could allow the crank excess movement,Also what type of flex plates are you buying I hope its not that cheap azz commie crap tin foil flex plates.

 

I'm on my third flexplate as well in a year. I found the culprit to be crankshaft end play.

 

Crank end play ot a misalignment between the crank center line and torque converter center line. Kind of weird though.

 

Is there a good way to test for crank end play? I had one guy tell me to take a pry bar and pry on the harmonic balancer and see if there was excessive movement.

 

Try that it will give you a rough idea.

 

The crankshaft has endplay and the flexplate handles this. Excessive endplay will crack out the center of the flexplate. Shims(between the crank and flexplate) are available to take up excess clearance. An auto trans with a rebuilt front pump will also cause excess clearance because the front pump was machined in the rebuilding process.