User 52121

Alright so it's tough to do a search for a clunk sound... I haven't seen it described the way it sounds to me, maybe somebody will have an idea.

Best way to describe it... word-wise, it's like a "toonk" sound. Took my dad for a ride last night (ex-master GM tech) and he described it (which I think is spot-on) like the sound a tin-can would make when you dent it. Slightly high pitch, and a "soft" clunk.

It's coming from the rear end somewhere. I can't consistently repeat it (which makes it all the more frustrating) but the most common time it does it, is on a light shift from 2nd to 3rd (like when you're rolling along in morning commute traffic, and gradually speeding up and going from 2-3). Step on the clutch and move the shifter out of 2nd and get the "toonk" and then I get the "toonk" again when I select 3rd and start to let up the clutch. 2nd most common is going from 1st to 2nd. Get the "toonk" as I shift out of first, and again when I shift into 2nd.

It does seem to be related to loading up the driveline... on rare occasion (it did it clearly last night)... say you come to a stoplight, you're on the clutch and brakes, get down to 10-15mph or so, and the light goes green. Stick it in 2nd and let up the clutch... and just past the point where the clutch starts to engage (and you start to load up the driveline)... "toonk".

If I step on the clutch, pause longer than usual, then shift - it NEVER does it. If I lug the car back and forth in gear, it never does it. Shifting under hard acceleration, it never does it. It doesn't do it in any other gears either. 3-4, 4-5 shifts, never an issue. Same with downshifts, never does it on a downshift.

Axle bolts are tight. Axles themselves seem to be in good shape. Pushing on the trans with my feet while laying under the car, it doesn't really seem like it sways or moves around excessively. My dad said it really didn't sound to him like it was "hard metal" (like an axle going down or the driveshaft or something). In the searches I did here, I found one thread where it was said that the trans mount failing was a "unique" sound. Wondering if that's what I'm hearing?

Any ideas?

Tom M'Guinn

Most rear end clunking sounds turn out to be CV joints. How old are you axles?

arthropraxis

Could it be the parking brake? Mine makes a rattle when going over bumps. Only heard when the windows are down.

blown 944

Have someone work the clutch while you lay back and watch the cv's. They may be moving laterally and hitting the flanges. I had this issue awhile back

racerxrick

Torque tube? I have a "tink tink" tin can sound when the clutch is out, goes away when the clutch is in..i.e. torque tube

User 52121

Huh for some reason I never got alerts for replies to this thread! Sorry for missing all these! Thanks for the attempts at helping.

Axles were replaced by the PO, though they have probably 40k on 'em now.

Compared the trans mount in my car to my Lemons car (which has a good factory mount) and I have a LOT more movement. Seems the mount is toast. If I push the trans hard enough I can make the passenger side axle clunk against the hub (which may very well be the clunk I hear). New Lindsey Ultra mount on the way, will put it in on Saturday and see if the noise is gone. Fingers crossed....

User 52121

Ok - trans mount replaced. BIG difference... wow. The original mount was still intact (as in the rubber wasn't broken in pieces) but it was SOFT and was pretty clear that the mount was worn out and resting against the stops. Got the Lindsey Ultra mount in and now the trans doesn't move at all. I do notice a LOT more engine vibration in the car at idle now, which frankly kinda sucks. Car was butter smooth before... now at idle it's a bit of a buzz. But whatever, no big deal. And thanks to the RL search function for telling me you could wiggle the trans mount + crossmember out the passenger side without removing the trans. Saved me a bunch of time!

As for the clunk noise - it's substantially reduced, easily 90%. But on *rare* occasion I still get the clunk (though even when it does happen, it's a lot more muted than it used to be). So the hunt is still on.

While under the car I noticed that there is a difference between the two axles. The driver's side, with the rear end up in the air, seems to center itself axially - in that I can grab it and slide it in/out along its axis, about equally in both directions.

The passenger side, however, seems to default to resting towards the outboard side against the hub. I can move it in towards the trans, but if I let go, it will slide back towards the outside. My hunch is that this movement is the clunk I hear (because if I move it aggressively towards the outside I can replicate a similar sounding clunk)... though having never paid attention to the axle movement before, I don't know if this behavior is normal or not. Any thoughts on that?

DDP

I have nothing worth while to add other than you drove past me at Pyott and Rakow. You wouldn't have noticed me in my BMW 3 series but I obviously noticed you and your car looks great.

User 52121

Saturday night? Aftermarket wheels and a little bit of rust on the passenger side rear fender going straight at that light while I turned right onto Rakow?

If so - then yeah I spotted ya, though of course I never would have guessed you were a RL'er. I would have figured you were someone from Euroteknik...

Thanks for the compliment on the car Wife and I were headed back from dinner (rare date night!) up at Kyoto's....

DDP

Ha! Yup. And I don't want to talk about the rust. IL is a cancerous state for a number of reasons.

Kyoto is a great place. Really nice now that they've redone it.

blown 944

I think you have probably Avoided a broken cv.

Good thing to get the mount sorted but the axle is still my guess for the noise.

I would do what I have done and use the vanagon joints (empi) and the 951 shafts. The joints are stronger and the 951 shafts are stronger. It's very easy to swap them and the axles are cheap. The only issue I can see is that if the axle end has been hitting it may be mushroomed.