Check the outer passenger side half shaft u joint--good bet it's shot, and very loose...just jiggle the half shaft, and it should move if the u joint is worn out...pretty easy to just look at it as well...I have had a couple go out on me, and what happens is all the needle bearings fall out of 1 of the 4 joints on that u joint, causing the whole thing to fail....

Good luck on finding the problem.

I can second dogma on that. Exactly what made my rear clunk.

Please see my comments on another thread called: "Bald rear tires". I have no better opinions than anyone else on this great site, I've just dealt with this very problem... very often, and yes 240s have mustache bars.

See yous guys!

72' 240z

Essentially, if you haven't replaced the front diff mount since the car was new....I would just go ahead and replace it first, (along with shaking the ujoints)...if the diff mount hasn't been replaced, its dead....you could almost bet the mortgage. An original or one you're not sure of is pretty easy to replace, and doesn't cost a leg either. Get the rubber mount, not the metal one, as the metal one will transmit that 'clunk' into your butt when your driving! (it is very much stiffer)...use the metal one for racing where you want less cushioning.

Resurrecting an old thread....

Does anyone have a picture of this front diff mount? I can't picture it as I am at work and I think I might have this issue. I thought it was the u-joints and replaced all 4(not the ones on the drive shaft) and the car still makes the sound. Especially when I start to back up.

Tx,

Bill

Sorry, duplicate post

Here is picture of it:

httphttp://www.courtesyparts.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=CP&Product_Code=55415-S30RD

Todd

Thanks Todd! Now I have to climb under and take a look at mine. As I recall, the band that fits of the top of the diff didn't seem to be even side-to-side. Need to look a little closer now that I know what I am looking at.

Bill

Hey Bill, just a heads up for you: I recently picked up the dreaded clunk as well. Having been on this list for a while, the first thing I did was get under the rear and try to move the front diffy mount. But it was solid. Lot's of head scratching...

After a few weeks, I tried the same thing again. Still "solid". But I noticed that the diffy is canted to the passenger side and is hitting/rubbing against the mount where the strap attaches. While I can't push the front of the diffy up, I can slide it side to side. So I have a new mount on order... Just be careful to not be fooled like I was if you can't move it up with your own strength.