I just took my Forester in for an oil change at a Firestone location near me, and instead.............they drained the transmission fluid completely and then overfilled the oil reserve. After they moved it out of the bay area, and out into the parking lot for me to leave it wouldn't move. I went to leave, and noticed it wouldn't move forward, so I kept messing with it, and really pushing down on the accelerator and it would finally move a little but it sounded weird also. After trying twice I went back inside and told them the car wouldn't move forward. They came out and checked it, and forced it to move half way across the parking lot by continuing to push the accelerator hard. Then all of a sudden this white smoke started coming out of the back of the car, and I am talking ALOT OF SMOKE! The attendant stopped the car, kept it running while he checked fluids, then had about 5 workers push it back into the bay. I went in there and was told what had happened. My question is.............would that hurt the transmission for that to have happened and driven only through the parking lot? They of course say no, but I want to make sure. I had them put in writing what happened and sign it.

Pay the $80 for a diagnosis at the Subaru dealership. If everything's fine, it's peace of mind. If not...

Sounds like Firestone may be buying you a new transmission, and they're lucky if they don't have to buy you a new motor, too.

Was this with an auto transmission?

This is why you should always change your own oil.