I searched the forums; didn't quite find a match. My 1973 240Z has new: Eibach springs, Tokico Illumina's (all 4 sides), factory diff mount. Previous owner installed a R-180 LSD, 280ZX 5-speed trannie.

I hear horrible clunking NOT when driving down the road or when shifting gears - my problem surfaces when I'm driving through the neighborhood (i.e. stop sign; turn left; stop sign; turn right). Sound is horrific. My mechanic said my u-joints were tight... what else should we be looking for to figure this out?

The limited slip itself. Many LSDs will make lots of clunking sounds in sow, sharp cornering.

Check diff mounts as well (particularly the front mount). They breakdown after 30/40 years and your diff will loosen up causing the clunking. You can search on diff mount and find plenty info here.

I have a 73 240 also w/auto. After totally going through the rear of the car and replaceing all bushing and mounts I still had clunking noise like you described. All u joints were good. My mechanic finally found it,was the spindle pin bushing on drivers side moving and clunking. He took it back out (newly replaced) and put some grooves in the tube so it was more resistant to sliding. Problem solved.I have had this problem since owning this car 3 yrs. problem got more pronounced since replacing the bushing. maybe this is your problem

I'm with Arne on this one . Take the car to a mall parking lot and do a series of figure eights . With a tight LSD ( you might have a posi unit ) it will clunk or " bang " . Probably isn't as pronounced on wet roads , right ? My old Ford Bronco got so wound up it would hardly want to turn until I put it back in 2 wheel drive ! It had posi lockers front and back , and hammered loudly when it loosened up going around corners . :classic:

I've not driven the car in the wet so I don't know if the problem is diminished then. The factory rubber diff mount was replaced last weekend.. that cured the grinding sound but amplified the variety of noises coming from the rear <g>. I have an appointment this weekend with my mechanic to go thru the excellent list of ideas...