72 240Z:

Approximately 6 months ago I replaced the stock rear control arm bushings with MSA urethane bushings because the outer passenger side pivit was clunking when shifting and going over bumps. The clunking went away with the new urethane bushings.

Now the rear passenger control arm is clunking again when shifting. At least I think that I have narrowed it down to the control arm bushings.

Last weekend I installed a tight 3.54 R200 with urethane mustache bushings, checked the U-joints and tightened all of the suspension bolts during re-assembly. And still I get a loud clunk from the passenger side. I also checked the stub axle flange and it is tight. The stub axles are new Nissan parts installed two years ago.

What would cause new urethane bushings to act like the old stock worn out rubber bushings? Could the metal sleeves be defective? Could the sleeve ID too big allowing movement about the pivit pin?

From searching the forum I know that the sleeves become locked in place once they are tightened down and the the bushing rotates around the sleeve, but it seems that if there was slop between the sleeve and the pivit pin the sleeve could move.

Thanks

Miles

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If you have tightened up everything else, it could be either a loose center cap on that wheel or a blown shock. I've had both problems and the center cap is sure easier (and cheaper) for remedy.

New diff mount? New arrestor strap? Did you also check driveshaft u-joints? How do you know your R200 is good? Did the clunk return after installing the new diff?

The only thing I'm aware of which would cause urethane bushings to behave like that is for them to be poorly made. Otherwise, I've heard rear end clunks being from strut bolts, rear control arms and u-joints, but you seem to have eliminated that part of the equation...Do a search for "rear end clunk" and see what I've missed...

If it's not that, then maybe something related more to your clutch is going to be responsible for the problem, since it's happening during shifts.

Mustache bar bushings.

Mustache bar bushings.

...recheck the nuts holding the mustache bar to the body and bar to diff, too.

What is center cap?

Tokico blue shocks are 1 year old.

The clunk returned after the R200 was installed.

I opened up the R200 and is was like new inside. The seals were in good shape but I replaced them anyway. Also, turning the input shaft showed no slack or clunking. The R200 is very solid while driving.

U-joints are tight. But I am going to replace all of them just to make sure.

Mustache urethane bushings are new.

All bolts were hit with an air gun and then torqued down.

Diff front mount is solid and installed with an air gun and torqued down.

A member at Hybrid had the same problem after installing MSA urethane bushings and it turned out the clunk was caused by the large front inner control arm bolt on the passenger side working loose. He solved the problem by adding a washer and locktight and re-torqueing that large bolt. I'll try that and report back the results.

Thanks

Miles

My clunking between gears which I had last Saturday which I assumed to diff strap/ mount turned out to be gearbox mount??? Accelerating when depressed clutch would get a clunk-clunk which seemed to be coming from rear. Got home checked strap and diff mount all good. Checked gearbox mount and found one side of the vulcanised rubber had failed. Not sure if I was just not hearing right where noise was coming from because had straight away assumed I new what was wrong. Just another option if symptoms sound similar.

Diff mount...

or...

Diff mount...

Hey, has anyone made or used one of those substitutes for the arrestor strap? The one that someone put out a drawing for and surrounds the front of your diff mount and housing. I need something after moving my R180 rearward the strap wouldn't go around it anymore.

A loose arrestor strap will cause clunking too. I am about to replace my front mount configuration with a setup called the Ron Tyler front diff mount. It replaces both the arrestor strap and front strap.

My clunking between gears which I had last Saturday which I assumed to diff strap/ mount turned out to be gearbox mount??? Accelerating when depressed clutch would get a clunk-clunk which seemed to be coming from rear. Got home checked strap and diff mount all good. Checked gearbox mount and found one side of the vulcanised rubber had failed. Not sure if I was just not hearing right where noise was coming from because had straight away assumed I new what was wrong. Just another option if symptoms sound similar.

It can get even worse than that. I've found that most all sounds appear to be coming from the far rear, even when they originate much farther forward. I literally spent months tracking down the clunk in my red 240Z. Started with the obvious and went from there. I replaced the following with new or known good parts from my other car:

Diff mount - new

M-bar bushings - new

Trans mount - new

All 6 u-joints new

Struts - new

Rear bushings - new

Swapped rear strut housings from other car to test bearings and stub axles

Swapped halfshafts to test splines

Finally in a fit of desperation I swapped the transmission -- and that cured it. Turned out that the countershaft bearings had too much end play and the countershaft itself was moving fore and aft under torque loads. I had to replace and re-shim the bearings in the transmission to cure it.