vibration/buzz problem in seat,floor & pedals

I have a 2002 GTP with 94,000km +- 60,000 miles, I've have this buzz/vibration now for the past 20,000km. It only happens once, only after I started the vehicle, and only after moving forward about 3-5 feet. It only last a second, but last longer if I really leave slowly.

I also seem to have a vibration at highway speeds(not the same intensity) it feels like I can sense all the roads imperfections.

Anybody have any sugestions on what it might be caused by? and if both noises are related?

sorry forgot to mention that the car also shakes between shifts, either at the end or begining of a shift (1-2, 2-3, 3-4)

sounds like a possible pwm solenoid/valve going bad. I would have said a shift solenoid, but since it does it in all shifts, I'd say it's a PWM.

sounds like a possible pwm solenoid/valve going bad. I would have said a shift solenoid, but since it does it in all shifts, I'd say it's a PWM.


PWM??

it's a valve in the front pump assembly that controls shift pressure.