1992 f-150

What would cause a fly wheel to break? It break in the center where it bolts in, I have had to replace 3 fly wheels.

How are you torquing the flywheel bolts?

Could it be assumed the engine or transmission was replaced in this truck and the problem started right after that?

If so, and I’m assuming this is an auto transmission, what is breaking is the flexplate, not a flywheel.
This problem is generally caused by the torque converter not being fully seated on the splines on the transmission. It may run like this but it will usually rip the center out of the flexplate.

This would mean removal of the transmission and making double sure the converter is seated; and I’m also assuming if this is an interchange job of some sort that the parts used are the anatomically correct ones.

Flywheels are on vehicles with a manual transmission. If the pilot bushing or pilot bearing is worn out… You have an automatic transmission, don’t you? If you do, it must be the flex plate that is breaking. Try buying a new one instead of a used one.

Maybe it would be good to start from the beginning and give us the ENTIRE story.

Improper torquing of the flex plate bolts and/or not applying a thread locker to the flex plate bolts.


Make sure the torque converter studs are going into the correct holes on the flexplate. There are two sets of four; one set for the muntinging studs and another set for the converter’s drain plug–whereever it happens to land on installation. Another isssue possibly causing this: If you have an AOD, replace the tourque converter…they were known for “balooning” during that period. You may notice fairly deep bolt head imprints on the converter’s hub. If you do see this, then I think you’ve found the problem…replace the 7902.