I have a 1997 Grand Prix GT Coupe, I just installed a newer 3800 in 2 weeks ago.

The car has an odd vibration while in drive sitting at a stop sign. Almost like a hum type vibration. Take your foot off the brake and it goes away.

Also this car's transmission has a sudden jerk type release sometimes when you are driving say 55 then take your foot off the pedal. Do I need to put a shift kit in it? It has 205,xxx miles on it, the Trans Fluid was changed last summer just before we bought the car.

Please let me know.

Thanks,
Vince