1st, a little backstory...
I had a fellow teener drive my 75 2.0 a few weeks back, and he commented that my gear lever was moving waaaay too much when he accelerated/decelerated, like my motor mounts were bad. I used the good Dr's motor mount test method (try lifting the engine with a jack while mount is all bolted up) and found that it wasn't the motor mounts (they held the engine down to the mounting bar just fine) but instead was the transmission mounts that were causing the issue, as the main nuts were barely finger tight, allowing the transmission to move around quite a bit. I tightened them up, and added lockwashers to prevent this from happening again...

BUT NOW, I have a very solid, and quite concerning clunk coming from the passenger rear of the car, ESPECIALLY when I accelerate and decelerate. It seems that the changeing load on the engine/transmission is moving something, but I cant figure out what???!! It really doesn't make any noise when hitting bumps, or changing suspension loading (corners, sudden stops, etc.) ONLY when I push the gas, or let off the gas and let the engine drag slow the car down. I checked the "play" on the axle, doesn't seem extreme. I checked the shock mount, the transmission mount (mustache bar?), the points where the engine bar mounts to the body, etc...

It sounds very solid, not body related, and I'm out of ideas and plan to crawl under her again today to try to figure it out... I'm concerned to the point where I can't drive the car again until I nail this down (literally ) HELP!!

Thanks in advance,
Chris

As many can attest, I'm no expert, but I'll venture a WAG and say it's a CV going out. Good luck getting it figured out.

trailing arm mount?

Check the 22mm nuts on the inside and outside of each rear trailing arm. If one is loose better check if the hole is still round.

I glanced at this, as it seems to be the area the sound is coming from (at, or a little forward of the wheel) but the road gime/dirt seal on the nut told me that it wasn't moving any... Obviosly I'll check it a little closer today. Is there some kind of a bushing in there that could be shot?

Why, yes there are bushings in there, one inner and one outer. They will make a heck of a noise. A rear wheel bearing will also make that noise.

if it was me, i would definitely check this. get the ass end of the car in the air and grab the insides of the tire and see if you can physically move it. rock it side to side, back and forth. if you cant see or feel anything, maybe remove the lower shock bolt and try it again....

I checked wheel play, it's not the wheel bearing. This trailing arm thing is sounding more and more like the culpret... weird that it developed so suddenly after re-securing the transmission... I would've expected the motor mounts to give up before the trailing arm bushings/bolt-up area.

In any case, its definitely on the short list of things to check out, thanks to everybody for the advice so far!

Chris

right thats what im saying.... if you rock the wheel "assembly" you will see or feel movement in the trailing arm pick up points. its easy to do.....

Lay on the ground and grab the axle shaft. Abruptly jerk it towards the transmission. If you hear a clunk your inner CV joint is old. Repeat towards the wheel.

Usually it's on the passenger side.

I prefer to replace all four if I find one bad. Get new ones from PMB Performance.

Was that the noise I heard when you were backing up? I was hoping not since we just got done with the transmission mounts.

I'm going to have to agree with Mark on this. If it was that noise it sounded more like a CV noise to me.

It's up on stands and I can't find anything. Gonna have the woman accelerate/decelerate with me listening near the area, that's the only thing I can think to try. I checked the axles, and they both will make contact with either the trans or the wheel/hub but only with quite a bit of force, should they not move that far with even a lot of force??
Thanks again everybody!
(feel free to swing by Jon )
Chris

I may be able to later tonight. I'll let you know.

Was there ever a diagnosis for this? Inquiring minds need to know.

Yes there was... but he may not want to say

Bowling ball in the trunk?

Funny you should say that. One time I bought a pair of 914 axles with CVs and put them in the rear trunk. Shortly thereafter I started hearing this 'clunk' when I would stop or start. Couldn't figure out what was going on til I got home and retrieved them from the trunk. Instant fix!