We finally identified what caused the 4" crack in the shaft log. About 18 monmths ago we had everything replaced from the coupler back ( coupler, shaft, cutlass) and also had new motor mounts done. Evidently the nuts must be torqued again after a settling in operiod of 9 months so both the from nuts dropped off the motor mounts. The engine shifted and laid against the shaft log and cracked it. New fix has backup nuts to prevent this from happening again.,
Covered under warranty..or..an excuse from the repair dealer that it was not their fault..??