Experienced the same issue just this afternoon:
Cruising down the highway at speed, attempt to pass another vehicle and the revís climb to 5k without any acceleration. Massive clutch slippage in any gear at any speed until the vehicle is shut off and restarted (at which point normal operation resumes).
No CEL, nor codes stored in memory (checked via ScanGaugeII).
Spoke to dealerís service department via telephone & should the issue arise again, I will limp the car to the dealer (without shutting off) where they will have their tranny expert meet me in the parking lot and accompany me on a test drive to verify the condition.