Aamco hosed a tranny in a pickup I had years ago. 1st and 3rd were slipping bad so I handed it over to them for a new clutch and gears. When I got it back, it ran fine for about 500 miles (drove back to school in NJ from MD) and the tranny just died as soon as I got to my dorm (luckily). Turns out, they didnt reseal it, the clutch was a lemon, and it just burned up because it was leaking juice. Needless to say, the battel went on and on for a few months while my truck sat in NJ until THEY paid to have it towed back to look at it. In the end, a Toyota dealer determioned what exactly happened and Aamco paid me a CASH refund and $1k for inconvenience.

Its not a pleasant fight sometimes, but most will fight you till you give up, even though they know they are wrong.