I recently had a transmission leak repaired on my 1997 Jetta GLS (automatic). It had been shifting roughly but drove much better after the repair (they also reprogrammed the transmission codes).
Recently I had a replacement muffler installed, and the mechanic put the car up on a jack, so that the car was tilted forward at a 45 degree angle.
Immediately after I left the place, the car started shifting roughly again. Is this a coincidence, or might this muffler mechanic have accidentally done something that would cause a transmission problem?