"Clunk" - Probably not what your thinking...

[Fishcop]

Not withstanding the tranny issues...

From the time I bought my car in 2000 there has been a clunk coming from the rear of my car. It mainly occured turning right and left and when I'd pull away. I did a whole lot of research and rebuilt everthing... CV's, TB's, springplate bushes, trailing arm bushes, dampers and their rubber mounts. The last thing was done last weekend... THE WHEEL BEARINGS Solved absolutely everything! Not an easy job, but very satisfying making my own removal tool and changing these out.

The car is not only travelling beautifully and absorbing bumps in the road, but it is doing it silently! Turns out my bearings were so bad that they were making noise I didn't even notice until it was gone

Just somethng else to consider Randy...

[rcecale]

G'day, John! Thanks for the info.

Haven't thought about the wheel bearings, but for a couple of reasons. First, I was able to actually duplicate the sound by moving the drive flange by hand. There is a bit of freeplay that doesn't exist on the driver's side. Either way, this slop needs to be tightened up.

The other reason is because I've "recently" had the rear bearings replaced. I say recently because it was done at 91500 miles back in 2000. Since then, I managed to put almost 11,000 miles on her. She's now sitting at 10280.

I suppose they could be bad, and I'll certainly check for any looseness while I have it up in the air, but I really think I have this pin-pointed to the drive flange.

Cheers!

Randy

[Fishcop]

Hey Randy! I see you're working on your accent

If you've done them recently then I'd say you're right and it's not the bearings. It was just an idea... I just couldn't get over the difference in my car after I changed them!

I look forward to seeing how it goes.

Cheers

[rcecale]

Well, had to take a few days away from the "clunk" to work on a chapter in the wife's Honey-Do Book. It passed "list" status years ago.

Anyway, drained the tranny case tonight and am extremely happoy to report that aside from a little bit of metal shavings, there was no cause for alarm like the last time I drained it. No wayward dogteeth floating around. Yes, I even made sure the fill plug came loose before the drain.

Case has been drained and the drain plug is tightened back into place with a good coating of anti-seize. The fill plug is waiting patiently to be replaced as well, once I fill the case back up.

Only about 4K miles or so on the trany since I had it apart and the Swepco looks a bit worn. Still blue, but it;s a lot darker than when it went in. A fresh load should do her some good.

Okay, now to the meat of the thing. I have disconnected the driver side axle and have removed the drive flange bolt. It does NOT have the little teat on it that I've read about. I don't think that is an issue, IIRC. Anyone?

Heading back out right now to remove the diff plate and have a look inside. I have the replacement seals from last year that I plan to install.

You know that advice you get that you wish you would have followed, but you didn't? Well, JW, you DID advise that I go into the diff last year when I had it out of the car. I sure wish I would have followed it. I'm sure I wouldn't be here right now, had I done so.

Well, back at it. I'll return with more in a bit.

Randy

[rcecale]

Trying to install the flange seal and saw where indigowhale said he almost put his seals on too far.



How far is too far???

Randy

[qikcpa]

have to second the info from fishcop. i had my car up in the air and could replicate the clunk (approx) by turning the half shafts. As there was some play I thought for sure it was the cv joints even though they were brand new when i got the car. I guess they could sell a bad one right. swaped the sides and still the clunk came from the right rear. cure turned out to be the wheel bearings.

[rcecale]

Originally posted by john walker's workshop
there you go. that would certainly do it. maybe compare both bolts for length. randy, didja swap in a different bolt when you did the trans? if that's the case, you could see the slop under the bolt head as the flange is moved in and out.

qikcpa, after spending the evening with it, I've been able to determine that the issue lies with item #3 in the pic I posted previously. Once again, John, you were right on the mooney!

With the axle disconnected, I removed the drive flange and then threaded the drive flange bolt into item #3 in the drawing. The slop I felt in the drive flange is definitely coming from item #3. I can hear and feel the same amount of freeplay with the drive flange removed.

John, is it possible to change this part (item #3) by removing the diff cover on the other side of the tranny? That would sure make it easy, if I didn't have to drop that tranny/engine again. Think it's time I start warming up my knees so I can commence kicking myself in the butt.

Randy

[rcecale]

bump

[john walker's workshop]

the whole diff comes out after removing both drive flanges and the side cover. don't drop it on your face.

[rcecale]

Thanks, John.

Should be back underneath taking the diff out tonight. I'll get a good charge on the camera battery too.

Randy

[rcecale]

Okay, following John's instructions, I removed the flange from the passenger side. (The diff cover and driver side flange were just tacked in place from last night.)

Here's the diff, ready to come out:


There was practically no resistance. The diff came right out. John, excellent advice about not wanting to drop this on my face. This thing has some weight to it. In my case, it probably would have hurt like he!!, but no one would have noticed the damage.

The removed differential:


Randy

[rcecale]

A couple of pics similar to the one JW posted.

In this first one, you can see the spacers flush against the side spider gears.


In this second pic, I have pushed inward on the spacers with just my finger tips. They are both rather loose, and when I push them, the BOTH move in and expose a gap that is a bit more than 1/16th inch.


It's dawning on me that I should go out to the garage and assemble the drive flanges to the diff and tighten then down to see if I can remove the slop.

I DID tighten the passenger side while it was all together last night. I was able to get a little bit of turning on the bolt, but it wouldn't seat the spacer. How soft is the spacer metal. Could it be stripped out? If stripped, how involved is it to replace it.?

Randy

[rcecale]

Alright, last post of the evening...

I followed indigowhale's tip in installing the new seal on the diff cover. Unfortunately, I didn't get a good reference shot of how far the seal needs to go in.

Going by the pic, should the diff seal be pressed in far enough so that the edge of it is flush with the ridge indicated in the pic?


Randy

[notfarnow]

Randy, you sure do impress me.

Thanks for reminding folks like me that an average guy with time and ambition can take one some pretty daunting tasks.

[rcecale]

notfarnow, don't let ME impress you. All I'm doing is turning the wrenches. The guys that impress me are the ones with all the knowledge! Without them, I'd be one of those "average guys" with no ambition.

After I was coached through repairing my transmission last year, I've found that a lot of things on these cars are a lot easier than I would have imagined. The key is knowing where to get your information, and when things aren't crystal clear in your head, come HERE and ask. If it weren't for Pelican, my local Porsche mechanic would be a lot wealthier.

Randy

[rcecale]

Originally posted by rcecale
It's dawning on me that I should go out to the garage and assemble the drive flanges to the diff and tighten then down to see if I can remove the slop.

Well, I did exactly this last night.

Inserted the passenger side drive flange into the diff and tightened down the bolt. The flange is tightening right up to the disc inside the differential, no doubt about that. What I'm seeing is that it's actually the two pieces, bolted together, that are moving.

I thought that maybe tightening the bolt would draw the disc into position and then snug up against it to hold it in place, but that isn't the case at all. As I stated above. Both the flange and the disc are definitely tightening up against each other. Once tightened, the two parts assembled is what is moving.

It's as though the stub part of the drive flange may be too long, which is odd, because these are the same parts that have been in the car since I've had it.

Any thoughts on this?

Randy

[rcecale]

bump

[rcecale]

Okay, took a break at lunch and took the differential to a local p-car mechanic. Showed him the slop in the in and out motion of the drive flange/disc assembly and he tells me this is normal. He then asked about my CV's and I told him that I had just done those a couple of weeks ago. He then suggested looking at the say bar because it's not uncommon for the brackets that mount the bar to the bottom of the car to come loose.

Climbed underneath and got my hands all over the sway bar. Everything seemed to be tight enough. Took a ratchet to all the bolts anyway, just to be sure, and they were definitely all tight. Kinda fidgeted with the bushings on these mounts and everything seems to be intact.

As I said at the beginning of this thread, "anything" is possible. I guess I can pull the axles and have another look at the CV, s. It really seems to me that the differential is the culprit. When the car was all together, and I worked the flanges in and out, it really sounded like this was the culprit.

Anyone have any other suggestions?

Randy

[fmarin]

It's been a while since there was a posting to this thread. Did you finally identify the source of the rear end noise?

I've been chasing a rear clunk noise that seems similar to yours. I generally hear it on a left turn "after" a right turn. Usually at lower speeds (e.g., when driving in a residential neighborhood). It gives the impression that something "loads up" on the right turn and then shifts on the left turn (which is when the clunk is heard). Centrifical force seems to be required.

I've checked all rear suspension components and replaced bushings, tbars, and engine/tranny mounts. A mechanic checked the wheel brearings and CV's. I don't know to what extent the differential flanges were checked.

Any ideas?

[Early_S_Man]

fmarin,

That type of directional clunk leads me to suspect that one of your anti-roll bar mounts has broken loose and is hitting the body on transistions from load to unload during cornering.