What is causing the car to jump when shifting from N to D? on 1990 Lexus LS400

I feel a sudden shock (jump) when I shift from N to D This problem happens only when the car is stopped and I shift from N to D This is not happening every time, sometimes the shifting from N to D is smooth Otherwise. the transmission is shifting very smoothly between all gears at all times Thanks for your help

by in Bristol, FL on September 18, 2012
1 answer 1 comment
ANSWER by , September 19, 2012
this could be several issue from motor mounts to high idle, and poss trans issues.seek a diag at aamco for free to make sure trans is ok then move to poss other issues
COMMENT by , September 19, 2012
Thanks for your help, Idle speed is normal, no error codes for transmission but sometimes I hear a loud sound of "whistling" when starting the engine in the morning before engaging transmission, this sound goes away after sometimes I think this sound coming from oil flow which is stuck somewhere in the transmission