clutch not fully disengaging 96 328i

[thisdavidg]

After driving with a clunk in the rear for some time, I finally had my car checked out. Turns out the clutch is not fully disengaging.

The clunk happens when I am pressing on the clutch and put the car in gear, mainly first and reverse.

Is there any way I can get rid of this clunk?
And how do I know if the clutch is disengaging all the way?
And what is the fix if it is not?
thanks in advance

[Steve530]

After driving with a clunk in the rear for some time, I finally had my car checked out. Turns out the clutch is not fully disengaging.

The clunk happens when I am pressing on the clutch and put the car in gear, mainly first and reverse.

Is there any way I can get rid of this clunk?
And how do I know if the clutch is disengaging all the way?
And what is the fix if it is not?
thanks in advance

Depends on what is clunking. This may or may not be fixed by making sure the clutch fully disengages. But since you know this is a problem, and it needs to be fixed, that would be the place to start.

Do you why the clutch does not disengage?

When the clutch does not disengage, it is usually difficult to shift gears at idle with the engine running.
3.

[thisdavidg]

it doesn't seem to be more difficult to shift with the engine on. I think that maybe the clutch is barely not fully disengaging. His does not happpen all the time. But most of the time I do hear the clunk.

[M52 POWER!]

My car clunks too and it's normal.... e36's with open diffs do it but M3's with LSD do not. I don't think it's anything to be concerned with unless it gets very loud?

[SQ Bimmer]

Does your car have a clutch stop installed? If so, get rid of it quickly as you do not want to cause any damage to your transmission. If the clutch is just plain not working and gears are clunking as a result, it would be be a very good idea to stop driving he car until you get the clutch fixed. Replacing the transmission is no easy task, and it's not cheap to pay someone to do it either.

[parolof]

It's not normal for a transmisson, or diff to clunk

[thisdavidg]

sounds like it's coming from the diff. Could the clutch not disengaging all the way be the reason for a clunk near the diff. I don't have a clutch stop and I do have an open diff.

[SLEEP3R]

i get the clunking sound also. seems to me that the clunking is coming from the back of the car and it isnt hard at all to get the car in gear. the clunking doesnt sound bad at all but it is noticeable and only happens when you come to a complete stop and then put it into first. any ideas what it could be?

[thisdavidg]

exactly

[AJGee]

So where are we at with this? Normal? Not?

Mine 'clunks' sometimes, usually when I'm rolling to a stop and put the clutch in and go into first after I'm stopped with the clutch still in. Sounds like it's from the rear. And yes, I've checked all the suspension stuff, no noises going down the road too.

And I can be completely stopped - dead still - and put it into first and it'll still do it, and the clutch pedal is to the floor. So one could assume that there's no connection to the tranny, and since I'm not moving, the diff should be at a standstill.

I was playing around with it yesterday, and it seems that if I wait a sec or two (after I come to a complete stop) it won't do it. Also, my clutch master cylinder leaks a tad, about a teaspoon every couple of months. But my shifting is fine, it goes into gear no problem.

So I'm going to go ahead and replace the master cylinder and do the CDV delete at the same time and see if that makes a difference. That's all I can come up with at this point.

And I guess there could be other things at work here. Perhaps when you transition from neutral into first quickly the idler shaft in the tranny is still moving a bit? In the diff? A bit of slop in the CV joints?

[Steve530]

In my experience, CV joints (not in BMWs) make a clunk when turning. It's usually the opposite side from the turn. Noise when turning left means the right CV joint is bad.

[AJGee]

Nothing when turning.. and besides, they're in the rear so they only move up and down..

[thisdavidg]

could the cdv delete take care of the problem?

[SQ Bimmer]

So the shop wont tell you what part(s) need replacing?

[thisdavidg]

just said that the reason for the clunk was because the clutch wasn't disengaging all the way. that's all they said. Also, it'd probably go away when I need a new clutch. My clutch is in very good shape and they see no reson to replace it just for a clunk. It would just be nice to figure this out though. There's gotta be a way to adjust where the clutch disengages. And I don't meen at the pedal.

[SQ Bimmer]

Maybe your slave cylinder is bad, or you have a slave cylinder fluid problem?

[thisdavidg]

would bleeding the clutch possibly fix the problem, and if so should I do the cdv delete at the same time?

[SQ Bimmer]

It wouldn't hurt to bleed your clutch, if you know how to do it. It would be a cheap fix if that was the actual problem, but I'm thinking it's most likely a worn clutch and or flywheel. If you have a CDV, then I would say get rid of it at the same time. That thing is garbage.

[AJGee]

.. I'm thinking it's most likely a worn clutch and or flywheel..

I'm not sure that I agree with this, at least in my case. My clutch works prefectly fine, and the clunk - when it does it - is from the back of the car. So even if his clutch is toast, there's still something clunking that shouldn't be.

I have another theory (again - at least in my case) that the tranny might still be spinning a tad and moving it to another gear causes some slack to be taken up in the drivetrain (in the u-joint or CVs). In my car, it seems to only clunk if I move it from one gear down to first quickly while stopped. And it's not even consistent, I can go days without it happening.

So this would say that the clutch may be dragging a tad, so maybe it's not a case of it not fully disengaging, but disengaging slowly. So back to the slave cylinder moving slow, possibly from a small leak in the hydraulic circuit, or clogging. Maybe the CDV is restricted?

My 2 cents.. I'm going to do the CDV delete as well and see what it does.

[percious]

Pardon me for asking, but does CDV stand for. Do I have one in my car?

-percious
www.percious.com

[AJGee]

Clutch Delay Valve - a fitting put inline with the clutch hydraulics that's essentially a restrictor. The supposed purpose is to buffer the actuation of the slave cylinder to smooth out clutch engagement. But in reality it makes the takeup point wander and some say that the slight slipping it introduces can actually accelerate wear of the clutch disc.

As to whether yours has one I don't know. They were on some models in various locations. Someone else here may know.

[thisdavidg]

AlGee,

It looks like we might have the same problem. If you get rid of your clunk, let me know how you did it. I'll do the same. It'd be nice if it was the cdv. I think there's a good chance the cdv delete will help.

[AJGee]

Will do - some of the earlier posts indicate that others have had this and haven't had anything bad happen, but I'm the paranoid perfectionist type.

You also seem to be getting it more severely than me - right now it's more of an occasional curiosity for me, but I had planned on doing the CDV delete for a while anyway. And like I said in an earlier post, my clutch master weeps a bit of fluid, so I know it's not completely airtight. And I might as well replace that while I've got the system cracked open.

I may get to it this weekend, not sure yet..

[Steve530]

Nothing when turning.. and besides, they're in the rear so they only move up and down..

Yes the rear wheels only move up and down, but when you turn, the wheels load up differently. The knocking during turns is a diagnostic for bad CV joints.

[thisdavidg]

My clunk happens even when I'm not going anywhere. Even at idle when I put in the clutch, as soon as I go to reverse or first the clunk happens. This doesn't happen all the time, just most of the time.

[AJGee]

And I'm the same, I only get it when stopped, wheels not turning. Except I'm just getting it occasionally, not as much as thisdavidg

[robisconfusedd]

the cdv will not fix this problem,

if the noise your talking about sounds like a DUNK when you put it in gear in your garage, then its your Guibo. i cant help you as far as how to replace it, do a search for it though.....

my car does this too but it doesnt bother me and i wouldnt think it could hurt the car any

[AJGee]

So guibo slop? (Sounds like a lunch special)

This would still mean that the driveshaft is rotating some when the clutch pedal is all the way in.

[AJGee]

Found this researching dual mass flywheels online - might be of interest:


"Cadillac's response to various "common" issues
CTS-V Unique Features Not Common with Other Cadillac Vehicles
Subject: CTS-V Unique Features Not Common with Other Cadillac Vehicles
Message #: CAS20040022
Corporate Bulletin Number 04-00-89-027 is currently available in SI.


Driveline Clunk on Declutch in Parade Type Driving


While driving in a steady, slow speed parade-type situation, a clunk-clunk noise from the driveline may be heard when depressing and releasing the clutch pedal or between shifts.This noise is characteristic of torque reversal of the driveline due to component architecture and is not a condition of operational concern. This noise may be slightly more noticeable on the CTS-V than the base CTS model due to rotating inertia of the large dual mass flywheel and larger diameter propshaft. This condition is normal and no repairs should be attempted.

-------------------------

WHY DOES THE DRIVELINE ON MY CADILLAC CTS-V MAKE A CLUNKING NOISE? (See discussion) (back to the top)

I have done quite a bit of work on the clunk issue since I have the problem on my CTS-V. The problem comes from the soft rubber torque coupling and the drive shaft center bearing mount. Both of these parts are made with rubber that is very soft to reduce road and gear noise inside the car. The clunk occurs when the clutch is suddenly released when there is torque on the drive shaft. The large amount of torque created on the dirve shaft in low, second, and reverse twists these rubber components like a rubber band. When you push in the clutch quickly this torque is suddenly released and the rubber parts quickly unwind. GM calls this torque reversal, but it is not actually a reversal. The clunk noise actually is not made by the drive shaft. The clunk comes from the ring and pinion gear in the differential box. When the drive shaft unwinds suddenly the pinion teeth impact the ring gear teeth and you hear the noise. The noise is loudest if you stand outside near the rear wheels. The noise is comming through the axles and into the wheels, but it is all caused by the soft rubber in the drive shaft. Some of this sudden unwinding is caused by the drive shaft itself since it appears to made from aluminum. Aluminum has one third the stiffness of steel so this causes some of the problem, but I think 90% of the problem is from the rubber. I have had emails on this subject going through the Southeastern Cadillac service rep to power train engineers at GM. Here is their response:

"The CTS-V driveline has a few "normal" operating characteristics that some customers may find objectionable. Obviously this is because the driveline was designed with high speed performance and durability as the primary criteria, pleasability issues that normally rank as high Cadillac priorities were relegated lower because this car is not like other Cadillac's. We know torque reversal in the driveline will cause an audible clunk and this can occur under various common driving/clutching conditions."

"Torque reversal is a result of normal axle backlash, the driveshaft rubber isolation flanges, the center support and the dual-mass flywheel working together. This phenomenon has been thoroughly evaluated by engineering and has been validated as not detrimental to durability or high performance usage. It is normal and no repairs should be attempted."

They will not give me the e mail address or the phone number of the engineer. Please send an e mail to: (email address removed at Robert Newman's request) and complain about this problem. Mike is the service manager for the Southeast and he will forward your comments.

You can create the clunk without moving the car. Put the parking brake on. Shift to first gear. With the engine at idle (about 1000 RPM) slowly let the clutch out until the engine bogs down to about 600 RPM. The very suddenly push in the clutch and you will hear about three clunks. Do not give the engine any gas when you are doing this. Just idle speed is good enough.

I actually blocked the car up very safely and got under the car. I trained my wife to go through this procedure while I was under the car, and I could see the drive shaft clunking back and forth.

In my younger days I was a power train engineer for off highway equipment so I know something about this issue. To me it is an unacceptable defect in the design of the CTS-V. So far Cadillac will not try to correct the problem. If you complain it will help. They tell me I am the only one complaining. The solution is to make these rubber parts from higher durometer (stiffer) rubber."

So maybe guibo slop, maybe gear backlash... maybe normal?

[thisdavidg]

My dad just bought a 96 328i thats just like mine. Anyway, I thought that there was no clunk for a long time as I drove it. I was still able to make it clunk by putting the car in gear. It is much softer though and sometimes not audible at all. This must be a wearing issue. But where?

[AJGee]

I'm thinking the guibo might be a bit soft, allowing some snap-back as described above, which gets heard from gear basklash being taken up.

[thisdavidg]

Are there different guibos that would reduce the clunk?

[AJGee]

Not that I know of - maybe a race part supplier would have a stiffer one. I'd try putting a fresh OEM one on there first.

[SQ Bimmer]

If it's really just the guibo, then just put a new OEM guibo in there.