Anybody ever broke a flexplate on a 4.0? I have a loud knock and think i have narrowed it down. Any experiences?

 

yes it happens all the time. to me twice my brother once already remove your inspection cover and look with a flashlight for black spider web lines.

 

Yep happened to me once. Thought it was the motor at first till I pin pointed the noise with a stethescope.

 

I was told by two different shops that the engine was trash and they would not waste the time to tear into it. After a little extra investigation when my brother told me to check the flexplate I found tiny little cracks around the bolts to the torque converter. Paid $15 for a used flexplate at the jy, paid $130 for a trans jack, and spent 8 hours spewing profanity in the driveway. Pulled the trans and found complete seperation around the bolts to the crank. Know I have no more knock and I have new tools for the next project I attack.

 

I wonder if this could be causing my No start condition has any one ever had the timing issues change due to flex plate/flywheel?
mt tac is not reading and on my snap-on scan tool its showing no rpms it has a new cps? But it hits on a few cylinders from time to time and try's to run.

 

the tone ring is part of the flex plate

 

There was a slight differance with the way my xj ran when the flexplate was cracked

 

I'm wondering the same thing about my no-start condition... Right now I'm getting spark to only one cylinder from the distributor. My XJ died during an offroad trip with rocks/mud/water. There is definitely some kind of obstruction (rock/metal?) in one of the twelve timing marks on the flywheel, and the CPS was completely melted when the XJ died. This leads me to believe there could be other problems involving the flywheel/flexplate...

 

is it common to go to this extreme? Have they been known to still run when this bad? Mine is probably this bad being as I can move it back and forth a couple of inches. Mine still starts and drives, just runs bad even at idle, no power, and sometimes I get a knocking from the bell housing, sometimes it goes away.