New info. I disassembled the whole rear assy. The old motor mounts are too large to fit in the frame by approx. .225". I contacted MTH about new motor mounts. If anyone has an older unit, you will need to get new mounts as well.
The rear frame is warped badly. The new frame is on top. Lower picture shows the motor mount on the new frame showing how much larger it is than the recess for it.