Drum won't spin during any cycle: passes all diagnostice tests.

The drum on my Kenmore Elite HE3t doesn't spin on the Rinse/Spin, Drain/Spin or any wash cycle. Each cycle will begin properly with water input, but when the drum is supposed to start spinning it doesn't. I have run the diagnostic test and the machine performs the appropriate action on each code, including drum rotation. The machine drains so I know the drain pump is working. I cleaned the drain filter (only minor sludge). I cut the power for in excess of 5 minutes hoping it would reset, but no luck with this either. What do I try next?