2006 mustang gt thump
 

Ok, guys, I hear a thump sound coming from the rear of my car during gear changes. Kinda sounds like something moved in the trunk, but there's nothing back there that would do this. For example, I accelerated and let off the accelerator then accelerated and heard the thump. I only have heard the thump noise 2 times, happened around 1st and second gear. Just got back from driving my pony around to see if I could hear it again but didn't happen again.

2006 mustang gt thump
 

Auri, worst case scenario, to much backlash on your ring and pinion gear. Better scenario, a worn rear grommet, which these cars are notorious for. Hope it isn't the Ring and Pinion.