I been working on the front suspension/steering this past winter and have finally completed it. Everything turned out great and makes a world of a difference when driving. But, let me get to my current issue. I backed the car out of the garage today and there was a noticeable clunking coming from the drivers side rear. It only does when I back up not moving forward. Any idea as what it might be, mustache bar bushing? Thanks

Could be bushings, but check all bolts for proper torque first. Chances are you've got one that worked loose. I had a similar problem when I got my Z back...bolts holding the diff to the moustache bar were finger tight.

Frank

Well got under her today to see if I could start the elimination process. I grabbed the driver side axle shaft and was able to reproduce the clunking noise, looks like the u- joint. Is this just a simple u-joint replacement or do I need to replace the axle shaft it's self?

Depends, there is one year of the 280s that used CV joints. I don't remember off hand which year it is. If you don't have CV Joints then it is a simple u-joint replacement. Suggestion. Do all four, otherwise you will be back under and doing the others real soon. I am not driving a drag car so I like the u-joints with Zerk fittings . When U-joints are assembled at the factory they grease the needle bearings with only enough grease to hold them in place for assembly. Be sure to lube them fully after installation if you use the ones with the fittings. Spicier to me are the best.

Gary

I decided to just grease the U-joints and that took the play out. I'll have to watch it to see if the play returns if so then I'll replace them. Just one other question. Once I had the axle shafts out I tried to check for play in the rear wheel bearings by holding the hub and trying to move in and out. I could not see any movement but I could hear some. I don't know if that is normal because there is no weight on the hub. My question is should I be able to see or hear ANY movement at all in the hub. Thanks