Symptoms of my Dual Mass Flywheel failure
 

Since the Freudenberg dual mass flywheel has been determined to be a weak spot on some of the earlier 964s, I thought I would post a detailed list of the symptoms my car exhibited after it's DMF failed over the weekend. This is a list of the symptoms on my car, and is probably not inclusive of every type of DMF failure (it can fail in several ways and there were apparently several versions of the Freudenbergs used in the 964s so the "sounds of failure" may not be identical).

First of all, there was absolutely no warning whatsoever. There was no gradual increase in noise, it just happened all of a sudden.

The first time I heard ANY noise, I was pulling out of a grocery store parking lot. When releasing the clutch I heard a really odd sound...sort of like a tire rubbing against a wheel well. This lasted maybe 1/2 second. After that the car wasn't the same.

On exiting the shopping center, where I had to stop and start the car several times as I manuevered my way out of the parking lot, I noticed a LOT of driveline noise whenever the transmission was put under load as I released the clutch from a dead stop to get it moving. Many vehicles will make a similar noise if you severly lug the car (like trying to slowly start a car from a dead stop in 3rd gear or driving at a really low speed in a high gear...15mph in 4th gear might be a good example). Unfortunately, this noise is occurring at "normal" operating conditions where the engine is revving at about 2000 RPM and the car is in first gear.

Another set of noises occurs at cruising speeds. With the car up to speed and cruising at about 45 MPH in 4th gear, if I took my foot off the gas suddenly, I heard a "clack" sound. If I then put my foot forcefully to the gas pedal I once again hear another "clack", and if I kept the foot down, trying to accelerate, I heard a driveline noise that sounds like it did in the previous paragraph when the driveline is EXTREMELY loaded, even though it isn't. These sounds are NOT subtle sounds by any means. I might go as far as to describe the clacking sound by saying that it sounds like every time you press or release the gas pedal, a little man in the engine compartment is throwing a power relay similar to that found in the fuse boxes found in homes (in my 30 year old U.S. house these are pretty noisy!).

The last set of noises that I heard happened today as I got ready to take the car to the shop. The car was cold because the it had been sitting for several days (since I first heard the noises) and the outside temperature was about 40 deg. F. When I started the car, I heard a rythmic clacking sound that would go away when I pushed the clutch pedal in. This clacking was MUCH louder than anything I had heard before, and it really sounded as if someone was rythmically tapping the side of the engine block with a ball peen hammer. As the car warmed up this noise toned down in volume and eventually went away. Once warm, the preceding paragraph pretty much describes all the noise I heard.

I've talked to several people via e-mail about thier DMF failures. Most people have described a loud rattling sound, and one person described his as sounding like "someone taking a tin can filled with nails and shaking it" (or something to that effect). My car had none of these sounds. Maybe it's just semantics, I really don't know.

A final thing that I should point out (I edited this after reading another post) is that during this, the clutch itself showed no signs of any problems..it engages and releases just fine.

I just thought I would post this for informational purposes.

<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" /> (Cheers! WELL...SORT OF, ANYWAY)!!!

Thanks Bill

-Dave
'90 C2 w/original Freudenberg and 46k

Thanks Bill.

Piers
1990 C4 w/original Freudenberg and 56K! Higher anyone?!

Thanks for the info. I'll be replacing my clutch this year so I hope I don't experience this before the r&r.

I have 106K miles with the original DMF!

Hi All

Since I purchased mine two years ago there has been a slight rattle when I turn off the engine which can be silenced if I depress the clutch pedal when I turn off the engine. This is the only sign I have.

90C2
Bill

Some time ago I participated in a survey on the dual mass flywheel issue on John Miles site. Freudenbergs reared their ugly heads in the survey, but not bad enough, I thought, to really ever make a firm recommendation that if the clutch needs to be replaced, replace the flywheel at the same time.

After having had this happen to me, I've changed my mind. FWIW, my official opinion now is:

IF YOU NEED A NEW CLUTCH AND YOU STILL HAVE A FREUDENBERG IN PLACE, DUMP IT!!!! GET A LUK!!

All I can think to myself after going through this is "how would you like to have been one of the guys who DIDN'T replace an old Freudenberg during a clutch replacement only to have to have ALL the work re-done a few months later." I've known people who this has happened to. Some mechanics apparently will argue about what they see as an unwarranted replacement, but I would just DUMP IT!!

This costs a lot to get done, and I knew I was facing this risk when I bought the car, unfortunately it couldn't have POSSIBLY come at a more inconvenient time.

Just my opinions.

<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />

Bill

Very Helpful - Thanks from me too!

Hi

I think my car is starting to have the same symptoms that Bill mentioned, a LOT of driveline noise whenever the transmission was put under load, a rattling when the car is stopped and it dissapears when I press the clutch,

My car is a 964C4 1990 with 60.000Km on it what are your recommendations, clutch change, DMF change... for which ones...

Thanks

ALEX

Alex:

It certainly sounds like a DMF failure, but you need to get it checked by a mechanic. Checking the DMF can be done relatively easily by a mechanic. I'm having them replace both the DMF and the clutch, pilot bearing...pretty much amounts to a full clutch job.

I'm not entirely certain the clutch really needs to be replaced, but at 30K miles, and no knowledge of what any of the previous owners did to the car (there is some evidence that the first owner may have tracked it several times) I figure why risk it? I don't want to go through this again six months from now.

<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />

Thanks Bill

What do you think of replacing the DMF for a single Mass Flywheel like the 964 RS.

ALEX

I have something totally different , but I think it's my clutch. On acceleration when I shift to second the RPM shows like my tires broke traction, but I know they didn't. A couple of times I started out hard in first and it felt like I didn't take my foot completely off the clutch when I know I did. Sounds like clutch, huh?

Keith, sounds like your clutch disc is worn out and slipping. Hate to say it, but you need a new clutch, and, as Bill pointed out, you might as well replace the flywheel while you're in there (assuming it hasn't been updated already).

Just a question?, If the clutch seems to work fine, but the DMF isn´t (rattling, etc...), would it be a good idea just to change the DMF? The car has 60.000 KM.

Thanks
ALEX

I'd probably replace the clutch too while in there, but I recently had still another question. With absolutely no evidence of a clutch or DMF problem, I recently wondered if I shouldn't just replace both anyway to reduce the risk of total failure at a most unfortunate time (such as far away from home). I started thinking about that when someone reported on rennlist having a catastrophic DMF failure while lined up to go out on track. His 964 was built about the same time as mine (early May, '92 for mine), so likely had the Freudenberg DMF, and his car had about the same mileage as mine (middle 40k as I recall). Bunch of racket followed by rolling his car back on the trailer and becoming a spectator; but, should that happen to me, I have no trailer! Made me consider replacing both without the slightest hint that either is about to go. On the other hand, the mechanic on my '88 once said that the clutch would soon need replacing; but I sold the car 40k miles later with a perfectly operating clutch. One just never knows. If I start losing sleep over it, I'll have them both replaced.

</font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Originally posted by Bill Wagner:
<strong>Alex:

It certainly sounds like a DMF failure, but you need to get it checked by a mechanic. Checking the DMF can be done relatively easily by a mechanic. I'm having them replace both the DMF and the clutch, pilot bearing...pretty much amounts to a full clutch job.

I'm not entirely certain the clutch really needs to be replaced, but at 30K miles, and no knowledge of what any of the previous owners did to the car (there is some evidence that the first owner may have tracked it several times) I figure why risk it? I don't want to go through this again six months from now.

<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Bill, maybe by now you have changed the clutch... but I read in a post here (regarding clutch noises) that it is recommended to also change the fork, needle bearings, and the slave cylinder while you are at it...

I am hearing a noise when I disengage the clutch... in my case the clutch was replace not so long ago, and I do not abuse the clutch (I floored once it is engage :D )... from searching the posts I found a few that made a reference to the slave cylinder...

Just thought I would let you know and it is not too late.