[Dave at Pelican Parts]

High RPMs with no torque, but still moving a bit, sounds just like a clutch. A failure in the clutch linkage (which is hydraulic, as Nick was pointing out) could do that, as could a failure of the clutch itself. But I cannot think of any way that a problem with the gear shift linkage could produce those symptoms. I can't even think of a reasonable failure of the transmission itself that would do that.

--DD