Pontiac G5 wierd braking and transmission problems?

My 2007 Pontiac G5 hasn't had any problems since I got it, and I already sent it in for the ignition recall to get it replaced free.

My car was in the garage and I started it and drove it to Lakeridge, and partway there, for about 30 seconds shifting started getting very jolty but then it stopped. At the same time whenever I hit my brakes there was a clicking sound from the shifter and this didn't stop. I parked at Lakeridge and shifted to park from drive and the entire car jolted.

After an hour I drove home and tried to replicate the problems but no more problems with the rough and joltiness, but the shifter continued clicking every time I hit hte brakes.

Anybody know what's going on?