Mine is only mounted with top mount as well. I have only 2 inches of rubber. Don't know if that helps though.
Looks good. 1 thing I hated about my buddies rig was the smooth floor on the passenger side. Feet flopped around like a couple of dead fish. Unsure of your plan for interior though.
Sounds like a bad motor. When my old 8274 went out it I replaced it with a warn motor # 68608. Bolted up great and runs very smoothe. Hope you get this thing figured out.:awesomework: