Zorba The Freak

My automatic 05 GT with 1,500 miles on it is experiencing these two problems with the transmission:

1. When shifting in "park" on an very small incline or decline the car will rock back and forth like an old pickup truck.

2. There is a very small vibration on the steering wheel when in "drive" and stopped with the brakes on.

Any people with the same issues?

---Also, I have the Flowmasters on it...should I take them off when I take it to Ford to check the transmission?

Thanks for any replies. :scratch: