on my 93LS, every time I put the car in D or in Reverse there's a thump and the car shakes trying to move in the direction that I've put the gear in, but i guess the brakes hold the car in place.
haven't seen this with other automatic cars. is this normal ? if not what am i looking at repairing ?

 

is the right fluid being used? Has the transmission fluid been serviced lately, and if it was, did the shop use Toyota T-IV fluid?

 

right fluid absolutely.
the car was only serviced at lexus. unless ofcourse they didn't put in the right fluid which i doubt. the trans fluid was replaced last year.

 

I had the same problem with my Ford. Check your gas pedal - it may be stuck giving extra throttle.

 

My '91 also does the same...
If I recall correctly, there were many other first generation LS owners who experienced the same exact thing you describe: a lurch or kick as shifting lever is put into Drive or Reverse. Has anyone found any solutions yet? maybe bad transmission mounts???

 

if the gas pedal was stuck then the rpm at idle would've been higher than normal so that can't be the issue.

 

As Azari described, my car still does this even with new trans mount. I kind of figured that the first gen was like this. So how many out there have this similar problem?

 

I have the same problem on my SC400. Bottom line on my car the drive line was the problem. on the Sc400 the drive lined is mounted via two rubber discs. one of my discs was damaged which cause the vibration when ever it was under prower, but would not be there when coasting.

the various parts are expensive, my solution was to replace the entire drive line, expensive but it worked. You or your dealer can do the inspection - good luck

 

i think its normal.. mine does sometin like that too.. i mean its nota brand new car you know? if lexus has been servicing that tranny, you should be fine, that tranny will last u a life time