About a week ago, driving in San Francisco up a rather steep hill (you know, where the sidewalk is a staircase), the car was unable to make it. Gas pedal on the floor, tach near the redline, car not moving forward. Started to slide backwards. Had to back down the hill. For the next week, no noticeable change in performance, despite concerns about having damaged the tranny. Yesterday, after driving about 65 miles started down a slight hill when traffic slowed to about 15 mph and the car started running rough. Traffic stopped. We proceeded forward from a stop but not at a normal pace: tach stopped around 2000rpm, but acceleration was extremely sluggish. Stopped again on a slight uphill and the car would not move (engine running, tach stopped at about 2000 rpm, but no movement). Put it in park for a few seconds, came back to drive and was able to limp to the side of the road, hearing a nasty sounding (but hard to hear) clicking through the driver side window. Shut the engine off for 10 minutes, started up again and the car behaved normally. Took it to a service station where we determined that the fluid levels are fine and no symptoms are shown. Drove the car back home (~65 miles) with no symptoms.
What does this indicate?