Clunk noise when engaging the clutch.

[PieEyedPiper]

I got a new clutch a couple of months ago and now, whenever I engage the clutch , usually from a stand-still I hear and feel through the pedal and floor boards some kind of clunk. Whatever it is, it didnt used to be there.

I'm a little freaked that maybe the holes for the bolts in my flywheel are ovaled or something or maybe my disc had its springs pop out or something?
Driveability is fine. But it does get some nasty chatter if I slip it wrong. (leading me to beleive the shaking and chattering might cause the flywheel problem i noted above)
Any ideas?

 

[jott5555]

its unlikely they would all oval out like that it would help to know what kind of clutch it was?

itcould be you broke a spring or something you can pull the boot around the clutch fork off and look around a little bit with a flashlight..

 

[toybreaker]

I would think a loose flywheel would vibrate and/or make some funky rattling noise. And it would change when you would push in the clutch...just a thought...

I can see how a clutch hub dampning spring failure could do some funky things..

I'd check all the bellhousing/engine bolts. It may be some of the hardware has come loose. I've seen a few chattering/clunky transmission problems appear a few miles down the road from a clutch/trans repair. If there was anything caught in between the engine and bellhousing during assembly like wires or the tab for the cooling tube, some miles will definately loosen things up.

While you're under the car I would also check anything else that may have loosened up, like the t-case and exhaust.

A loose/torn transmission or motor mount could also give symptoms you're describing.

Good luck, and let us know what you find!

 

[jott5555]

ya i was going to suggest maybe could you have put the TOB in incorrectly and did you make sure to put that little half round clip thing back on it when you reassembled it? one bad tranny mount wouldnt really do anything because on the tranny of a 2g there are 3 mounts but check em anyway..

and make sure all your bolts are nice and tight.. also check the xsfter case if that were loose it would also rattle around like that..

 

[PieEyedPiper]

Thanks for the ideas guys, I'll make a list and check 'em of one by one.
I too believe it's unlikely the flywheel is loose/ovaled bolt holes. I'd be experiencing worse symptoms.

I've narrowed the issue down some today. It's not so much the engagment of the clutch (though it is indirectly related - and still produces the clunk), but rather, load on the drive train.
If I apply throttle when the rotation of the driveline itself is low, then I experience the clunk from the transfer of load from the engine/tranny to the drivetrain.

I crawled underneath and things looked a tad rusty. I took a can of pb blaster and hosed down anything that looked overly rusty or that had a joint/bolt in it. Hopefully that will lube and prevent some of the rust form getting worse for the time being.
I've yet to find the source of the clunk, but I do know that my carrier bearings are still working dandy so its not that issue where the driveshaft is literally hitting the bottom of the car when under sudden load.

 

[toybreaker]

It sounds like you're making progress narrowing it down.

I believe there's a vfac on the carrier bearing thump problem and one possible fix, but I'm a maroon and can't do the cool guy post a link thing...maybe someone else could help us out...

I have wondered about the carrier bearings flexible collar myself...the driveshaft looks centered up on some cars,..and on some the collars look all saggey..and the driveshaft is almost touching the housing on the bottom. I can see how things would kind of wind up and clunk if the collars were weak. I would look really hard at the mounting bushings for the carrier bearings as well. I've seen a couple of the bushings deteriorate and let the whole carrier bearing housing move against the underbody.

The carrier bearing collars on my 92tsi are pretty well centered up.I've grabbed a hold of the driveshaft in my car and moved it around, and I was suprised at how soft the collars were...if'n I had more than the 46 tease: ) horse I have now.. I could see how it might make some noise when the driveshaft bottoms out against the carrier bearing housing...

Good luck, and keep us posted on what you find.

 

[PieEyedPiper]

Alright, I just put the car up on jack stands and crawled underneath it to get a better look at everything.
The rust situation isn't as bad as I thought. I used some Rust-o-leum paint to cover up any spots that looks like they could spread.

Nothing seemed loose, and i grabbed into the tranny and wiggled with all my might to find it barely moves in any direction and when it does move it does so in a slow and dampened manner. I don't think my problem is a loose anything right now.

I grabbed onto the drive shaft (front and rear) and it also moved very slowly and very minimally. The carrier bearings are still pretty good and it would take a very large bump for the driveshaft to move enough to hit anything.

During my grabbing of the driveshaft (all jokes aside) I noticed it had some play in the rotation. I do not know if that is normal. When I rotate it the 1/4 in. of travel is has in each direction I'm met with a very similar clunk sound that I experience when I apply load to the drivetrain. The noice comes from the transmission for sure. Which is probbaly why I can feel it through the floor and pedals.
So assuming that this clunk when I rotate the driveshaft by hand is the same clunk that is emitted from giving the car some gas - what would be the issue I'm dealing with?
I'm unfamiliar with anything-transmission or even drivetrain related so I'm doing the best I can.

Also I noticed that when I rotated my front wheels by hand (with the ebrake off!) the rear wheels did not budge, and the opposing front wheel rotated in the opposite direction.
Should not all 4 wheels rotate in the same direction and at the same speed?

When I rotated just one rear wheel by hand I experienced the same symptoms. The opposite rear wheel rotates in the opposite direction while the front wheels remain still.

I decided I'd test further by turning on the engine and letting the car sit in first gear.
All my wheels turned - but at different rates...but at least they were all going in the same direction now.
My right front spun fast.
My left front spun slower.
My right rear spun super slow.
My left rear spun fast.

I could stop every single wheel by hand while the other 3 wheels continued to rotate. After I let go of the rear right wheel (the slow one) it had a hard time starting to spin again.
The front tires, however, could still rotate easily while the rears were stopped.

Is this correct? Something must be wrong here - even if it is unrelated to my clunking noise.
Also I can find no signs of an LSD sticker in any door jams or under the hood of the car.
I know how a car would react if it had an LSD, but assuming I don't have one, what would my car ideally act like?

I know this is a tonne of info etc, but I hope someone can take the time to address each of my concerns.
Thank you!

 

[toybreaker]

I don't have a 2g, but on a 1g there's a sticker on the drivers doorjamb right above the vin data tag. There's also a sticker on the rear diff. case cover, by the fill plug.

As for running your car on jack stands....

I would strongly caution you to be VERY carefull doing this...If you put the brakes on abruptly, or anyone of a number of things upset the car, some really bad things can happen really fast!!! (I don't even like doing this on a lift either...especially because the suspension is at full droop, and the driveshafts are working at pretty extreme angles.) Make sure you have somebody in the drivers seat that can safely shut the car down. Sorry, I'm old and I've seen bad things happen...and that makes me really nervous!!!

It would really suck to get whacked by your own car WTF

Without traction to hold everything at about the same speed, all the diffs, front, center, and rear will all be spinning at slightly different speeds. The wheel with the least resistance will spin the fastest and the wheel with the most resistance will spin the slowest. If the car has a functioning viscous coupling in the rear, both wheels would be turning about the same speed... Since you can stop one wheel..and it doesn't spin back up...it's safe to say your rear diff is not an lsd, or if it was, the couplers viscous action is no longer functional.

With a correctly operating lsd rear diff, turning either rear wheel will turn the oposite rear wheel, as well as one of the fronts in the same direction.

With an open (or broken lsd) diff, rotating a rear wheel will rotate the other rear in an oposite direction

Holding either front or rear still, and turning the other wheel on the same end *should* turn the entire driveline, including at least one of the wheels at the other end, thru the center diff.

As a final test, if you put the e-brake on, and hold one front wheel still, the other front wheel should be REALLY hard to turn, as it's got to make the center diff, and viscous coupler work inside the trans.

My 92 tsi has the lsd stickers, and after this winters snows, the rear viscous coupler took a dump, and acts just like yours.

Both my 90 gsx's have effective rear lsd diffs. When I try and comp the heads on our alignment machine,..it takes three people to hold the wheels stationary in order for me to set up and level the alignment heads at each corner...and it takes a suprising amount of force to do it.

I hope that helps. I don't consider myself a driveline expert at all. That's just my understanding of how things work.

Good luck, and keep us posted.

 

[Strm Trpr]

So, you say you put in a new clutch a while back, and all was good.
Now all of a sudden you are having this clunking issue when you press the clutch pedal in.

I hate to mention it, but have you checked your crankshaft endplay?

Here's a link that mentions how I measure my crankshaft endplay.
http://www.dsmtuners.com/forums/showpost.php?p=1790199&postcount=8

 

[PieEyedPiper]

Thanks, I'm positive I'm not dealing with Crankwalk, however. I have no other symtoms, except a "clack" ( I listened closer, so its a clack and not a clunk.) when I apply load to the drivetrain.
It's not directly related to the clutch.

As for running the car on stands - I practised safety procedures here. I let the car idle in first, an infant can crawl faster than the rotational speed of the wheels. If the car did just somehow fall off all 4 platform stands it would immediately stall when a tire hit the ground. Professionals do it all the time and I'm fairly confident that under the circumstances it was a safe procedure even at my novice level.
But I do thank you for the reminder that saftey is key when doing anything like that.

As it turns out, my car does NOT have an LSD as there is no mention of it anywhere, not door jams, not yellow stickers, and no notice on the rear end by the oil fill.
I seriously wonder WHY the original owner did not purchase the car with an LSD but included every single other option availiable.

I think I understand why when you turn one wheel (any wheel) the opposite wheel will spin in the opposite direction ( I think).

Howveer I'm still confused why all wheels would spin at drastically different rates, even when using an open diff (is that what mine is?). I understand there will be slightly different resistance for each wheel but this was a pretty radical difference in rotational speeds. Maybe I'll make a different thread for that concern.

My main concern right now is the "CLACK" I get in the driveshaft where it dissapears into the front of the car.
What causes that kind of play?
How can I take it apart to look at it?
Is there an easy way to dismantle that?

Thanks for your help guys.

 

[toybreaker]

I'm glad to hear you take safety seriously. I'm kind of a conservative ninny, but I still remember when technician A put a car into the wall...with his tool box in between.

I'm not completely sure if running the car without a road surface reference teaches us anything usefull. I've done it myself, and I had myself pretty convinced I had burned up the pumpkin in one of Z cars...only to figure out later that the angularity the driveshafts were running at with the suspension at full droop created a noise and vibration that didn't exist when the car was at the normal ride height. And it kind of favored one wheel over the other as well. I think it's just a function of which wheels have more or less resistance as to which spins faster or slower....I don't think it matters.

If you could take a diff apart and spin it, you'd understand it immediately.

Winding up the driveshaft and hearing it clunk inside the t-case/tranny can't be good.

There's about eleventy million moving parts inside, and the possibilities are almost endless. Some likely problems would be excessive back lash in the geartrain, center diff, front diff, or t-case bevel gears.

On my 1g, most of the backlash, and noise, are in the splines between the t-case and tranny...it sounds bad,..but it's been that way since I got the car 85k miles ago...but other than that I don't know.

Good luck, and keep at it! You're getting closer to finding the problem.

And, please keep us posted, I'm curious to see what it is!