So the saga continues.....
The C5Z is up on a lift and the drivetrain is out.
The Centerforce Dual Friction clutch disk looks OK, but the pressure plate and flywheel have noticeable burn marks on them.
Of particular note is the amount of residue of *something* around the pilot bearing. Actually in this case, it is a pilot BUSHING.
There also appears to be some sort of wear striations inside the pilot bushing.
The portion of the torque tube input shaft that rides within the pilot bushing looks like this.
Appears to me that the pilot bushing is damaged. But whether that is the cause of the problem or the result of something else that damaged the bushing, not sure at this point.
I have been talking with RPM Transmissions, and apparently putting in a pilot bushing instead of a pilot bearing is not recommended.
So, the jury is still deliberating....