2000 Ford F-150 accident

Transmission problem
2000 Ford F150 V8 Two Wheel Drive 130000 miles

my truck was at the shop for brake service when I returned to pick it up they told me it had slipped and fell off the lift causing body damage they took responsibility for the damages it was in the the shop 30 minutes later for repairs after a week in the shop iget my truck back only to find out its making some weird sounds I dont know if its my transsmisson or my muffler can you give me any advice on what to look for or questions I need to ask