I am not familiar with how they run their shafts, but most trainers have an inner shaft and a larger outer sleeve that the tire rides on. The two are typically held together with a recessed allen set-screw through the outer sleeve - locking it to the inner shaft. To me it sounds as though your set screw is loose (if equiped).

If not, and there is not fluid leaking, and the tire is not slipping then you have a bum unit.

I highly doubt this is the case.

Do you hear fluid moving through the unit when you spin the roller by hand? Put your ear next to it.