When i shift from park/reverse to drive my 2006 Lexus is350 makes a clunking noise. The noise comes from I could say the back of the car. I did some research and found out it could be the universal joint. Is there any way to replace this u-joint or should I go ahead and purchase a new drift shaft.

 

Sounds like you're guessing. Get it up on a drive up rack and have someone look while switching gears.

The bushings holding the rear diff are highly suspicious. i.e. the diff moves up and down making the clunk when switching direction.

 

With your foot hard on the brake (AKA, not moving at all), does the noise still happen when shifting OR does it only happen once you release the brake and start moving backwards?