03 C4 Drivetrain play

Apologies folks. I think I posted this question just now in the wrong bloody place (someone else's thread) so I'll try again. I have an '03 996 C4 with about 79k miles on it. I've owned it about a year and it's had this odd charateristic all the time, but I wanted to get it checked uot before my 1yr warranty runs out. Anyway, to the point! When changing up, at relatively low revs (say 1500 rpm from 1st to 2nd or low revs up through any gear), there's a definite "clunk" coming from the rear of the car. Sounds like play in the drivetrain. Took it to the dealership yesterday and took one of their senior techs out for a drive, demonstarted it to him, then he drove it. He could see what I meant, and so he took it for a drive with the shop foreman. When they got back they removed the belly pans and checked out all the mounts and the UJ's etc. Found no problems! They're not sure whether this is "normal" or "typical" for this generation of these cars so they're finding another 996 C4 to check out to see if it's the same. They will then call me and I'll go check out that car also. So they seem to be trying at least! If I drive it a little quicker and don't change up in any gear until say 3k or above, the "play" is just about gone or at least, undetectable, but slopping around as if I was driving a shopping cart, definitely demonstrates said problem. Thoughts/opinons anyone (other than just drive it higher in the revs...:-)) Les.

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Do you hear any whine/howl (however faint) from the car? That you didn't get they all do that suggests to me that the noise is more than what can be called normal drive line play. Maybe. Maybe the dealer/service department is just giving you good service. So, let the dealer/service department move ahead and hear what they have to say, what the findings are. In the meantime, FWIW, with both my Boxster and Turbo I seldom shift up at just 1500 rpms preferring to at least rev the engine up to over 2K to maybe 2.5K. Once in a great while I hear a clunk, but it is not bad at all. The reason is I just get sloppy with my clutch work. The transmission/diff gears will have some play, not much but some, and then the CV bearings also will have some play. Again not much. But the result is additive. It could be your car has just a bit more play/clearance at one or more places that while this extra clearance is still within tolerance it does means the car is a bit more prone to clunking and your habit of shifting at lower rpms means you are just more likely to hear it. Just a thought, but be sure if you have not had this done, have the brake fluid flushed/bled and along with this the clutch fluid. If the fluid is left in service too long, 2 years is the scheduled flush/bleed interval, clutch action can get a bit affected by this. With fresh fluid the clutch's action will be as smooth as it can be. Sincerely, Macster.

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Thanks for replying! No howl or whine at all. I do think the dealership is in fact trying their best. Been very pleased with them so far since ownership. Interesting you mention being lazy on the clutch. If I try to get a little "early" with the clutch, no noise! Maybe this car/clutch is just different enough that I need to use it differently?? The clunk isn't really bad it's just that I figured it shouldn't be there, but if it's me and my poor clutch work, well, not the car's fault! I personally haven't had the clutch bled. Good idea. Les.

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I've been driving more years than I care to count and mostly manual transmission equipped cars. I won't list the vehicles but maybe 9 or 10 all told and only one (a pick up truck) was an auto. I pride myself on knowing how to properly use a clutch and shift a manual. Nothing fancy, no double-clutching, no trying to not use the clutch, no power/speed shifts, etc. I use the car drive the car spiritedly sometimes but I still have some mechanical sympathy for the clutch/transmission (and the entire car) when doing so. Over the years, I have gotten very good service life from clutches: one failed prematurely (at 18K miles) and was covered under warranty and another failed (throw out bearing failed) after over 120K miles) but the rest in used or new cars never gave me any grief; and transmissions: no manuals have ever needed any attention. When I first got in the Boxster, well, not at first, but after I bought it and after I had it for a few days and in acclimating myself to the car, I was finding that I was driving less like a skilled experienced driver but like someone in his first manual car. Take off from stops was sometimes rather ugly. I would nail it a few times, feel pretty good about myself, then pull a real boner of a take off. Lots of clutch slippage and rpms. Embarrassing and it had me worried about clutch life. Now before the Boxster when I was in a car I preferred to sit a bit closer to the wheel and this choice of driving position has worked very well for me through the years. But on a hunch, I moved the seat back some -- the seat is actually back all the way and the seat back reclined to where it just clears the carpeted panel behind the seat and the seat bottom is down as low as it will go -- and while this position felt odd my clutching improved greatly. I'm not sure why. Maybe because sitting further back I'm using more foot/ankle (and the ball of my left foot) to let the clutch pedal up rather than the leg muscles and the foot and ankle give me more precise control. Since this and even now moving the car off from a stop and shifting is once again smooth and without any drama. And I must have hit upon an efficient technique for the car now has over 255K miles and the clutch is original. The further back position while strange to me at first but now seems natural as all get out. Just a thought. Sincerely, Macster.

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Very interesting because like you, I've had a lot of manual transmission cars over the years (i'm 66 and also drive a '68 XKE and also ride bikes), have always been very easy on clutches, but this experience is definitely different! I was sure there was something wrong withe car, but now, reading the replies, I'm am not so sure!! I hope the car is fine and it's really just me. Oh, and btw, my "launches" have, like yours, been a very mixed bag of good, not so good and downright embarrasing. I mean, it's bloody annoying when a Civic can sometimes get away quicker and smoother than my one-time $90k car!! Thanks for sharing. Be glad to hear from anyone who has a C4S that has experienced something close to what I am experiencing. Les.

I've never shifted below 2500, but I'll try it and see if I get a clunk.

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Interesting Mac. I am only 5ft 9inch tall but I also, have my seat all the way back and at the lowest setting and I also, have no problems when clutching. No clunking or over revving. It just feels right. When I went through an advanced driving course many moons ago. The trainer told me that clutching should be as smooth as possible so if a glass of water was on the bonnet, the water should stay in the glass. Now I know thats virtually impossible especially in a 99 C2 carrera but I try to achieve that goal in my clutching and rev combinations. I have been driving manual for 53 years and I have never had a clutch changed in any of my vehicles. BTW this is the first vehicle that I have had to keep the revs over 2500rpms at all times.

The clunk may also be the *dual mass flywheel hitting it's stops. 1500 is very low rpm for smooth consistent shifting to next higher gear. These engines like to live @ ~3k *For reference: TSB 911 (996) 8/02 1360 Dual Mass Flywheel Check procedure http://www.renntech.org/forums/index...-procedurepdf/ Can the dual Mass Flywheel be twisted approx. 15mm in each direction, left/right, and does it return to approximately its initial position? If so it is good. Can the DMF be twisted beyond dim stated above without a noticeable increase in the spring force? Or is it fixed (no rotation?) if so bad

Just about any car and especially one with an auto can beat either my Boxster or even the Turbo off the line, unless I choose otherwise. Without much drama both cars can move pretty darn quick off the line when I want them to. However I move off at a pace that is within the context of the traffic around my cars. There's no need to make every red light start into a drag race. I know how fast my cars are and I know which cars are faster and which are not faster. No need to beat on my cars to constantly remind myself that either car, and especially the Turbo, are darn fast cars. So, I let the riff raff have their fun from the stop lights. Chances are long after those cars a worn out worthless junkers my Porsches will still be looking good and running just fine and can if when I want them to, when I call upon them to do so, still deliver the impressive acceleration and high speed cruising performance/handling and the big (155mph Boxster to 189mph Turbo) V-max they are renown for. Sincerely, Macster.

I tried it a couple of different ways and in different gears. No clunk, but it was certainly boring. As I've discovered each of these cars can be a little different with nothing being wrong with them.

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I agree, my point was really that this car is much easier to fluff the getaway than just about any other car I can recall owning. It really does sem to be a unique beast!

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Sorry man but I didn't see if your car is AWD? if so, that suggests to me that there might well be something amiss with mine.

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Great analysis of the ins and outs of the Porsche car Macster. At first I would gun it to find just what it was actually capable of and many times as I arrived back at the garage I would find myself saying aloud "You are one gorgeous nasty viscious little ba****d" or words to that effect. In the past, I would wait for a fast looking car to tailgate me along the country roads and leave them for dead around the lanes. The temps would obviously but up high before attempting anything like this move. Not so today. I take a quiet comfort in actually knowing what my car is capable of and in most (but not allcases) I restrain myself and give the other drivers their heads. I live, breath and dream about my car. All day, from the time I first awake to getting in bed. I never fealt this way about any other vehicle I have owned. Mine is an all year DD.

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AWD brings with it a cardan shaft (runs from the tranny to the front diff) the front diff and the axle half shafts and CV bearings. The clunking noise could be coming from one of these components. I remember a while back someone found his Turbo's cardan shaft shot well the bearing at the point the cardan shaft entered the front diff. Since I own a Turbo which is of course AWD and was a bit worried about how to spot this early (while my car was still under CPO) I talked to some techs about this and they told me they have found very few AWD systems go bad. Just one or two in the population of cars they've worked on over the years. The symptom something's wrong is the bad thing is noisy, whatever the bad thing is, all the time. But a clunking noise might be a new failure mode or just one they never encountered. Also, as someone else posted the dual mass flywheel might be bad. But if I recall the car is at the dealer and or will be for a thorough check out and the techs will certainly eliminate any AWD subsystem components along with the dual mass flywheel from the list of suspects. Or they'll id one of the above as the suspect, the source of the noise. Sincerely, Macster.

DMF does not have to be bad to clunk a little with a less than stellar shift. Could also be a worn/bad flex disk at the front of the cardin shaft. Porsche only offers the whole $haft if it is the disk. Driveshaft flex disc - C4 and Turbo These folks list the OEM Porsche replacement for $85, KO Performance in Florida. Search the book number. http://www.koperformance.com/ Part #: 102539005-57 KO Price: $84.61 Shipping: $0.00 - FREE Shipping! - & *Ship Group Stock Status: In Stock - Ready to Ship! ---------------------------------------------------------------------------------------- Book #: 10 2539 005 Description: Driveshaft Flex Disc Applications: Carrera 4 99 thru 05 Manufacturer: O.E.M.

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Great info and link! Thanks man!

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Turbos are AWD. Same system as the C4S.

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The dealer has dropped the belly pans and checked out all the apparent components without finding any play. This is good and bad news, imo. Good in that there's nothing apparently wrong with those components, bad in that perhaps the problem, if there is one, lies on the interior. The Service Adviser mentioned that he thought perhaps there might be a problem with the pressure plate.......not providing immediate and clean separation I guess?? The clutch on my car is in fact a lot heavier than the clutch on a 2002 C2 I drove while at the dealership this week. Is the clutch on the C4 supposed to be heavier than on the C2 model? Also, how difficult is it for the home mechanic to replace the clutch themselves? I do have the garage space and a two post life. Also have worked on and restored many cars over the years, but this is the first time I've ever owned a Porsche and NEVER worked on one. I'll bring the thoughts of the cardan shaft and bearing to the attention of the dealership. Once again, thanks for all the help and good advice! Best Les.

Just as easy as most other cars. Do a search for IMS replacement threads. You need to support the engine as the trans mount acts as one end of the engine mounts. Here is one: https://rennlist.com/forums/996-foru...s-bearing.html The clutch should be as easy as C2. Some reasons for heavy clutch are: Worn disk changes the geometry of the clutch fork assy increasing force required to press clutch in. Broken/removed helper spring (clutch pedal shaft - small can above your foot) Long story about clutch helper spring https://rennlist.com/forums/996-foru...matically.html

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Thanks! I took a look at the link re clutch assist spring. The word "heavy" as it relates to the required pedal pressure........subjective I guess. I think the pedal pressure on my car is heavy enough without maing it more so. I can feel a certain "squishy-ness" when using the clutch pedal. I now think it's the spring making some noises etc. Might try to get under there and take a look to see if it's broken! Looks like removing the bits and pieces to replace the clutch isn't that bad at all, but I agree, bit of a nightmare without some way of getting the car well off the ground. Oh boy, how that brings back memories of scrambling about under cars using only ramps when chaging out clutches......back in the day when I just about had a pot to pee in, but not much more. Thanks for the help and guidance. Les.

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Can't jhelp you with the clutch question. I've never done a clutch in any of my Porsches and so far neither the Boxster (256K miles) nor the Turbo (92K miles) have required a clutch. When (if) a car requires one since I have nowhere to work on my cars, do not have the proper equipment anymore and so on, I'm just going to let the dealer's service department replace the clutch. My WAG (based on what I've read here by those that have done it themselves is that the job is not that hard a job, but you want to be sure you have the best DIY and have the proper equipment. For instance when my Turbo's 6-speed transmission was being replaced the tech supported the engine with a special engine stand while the car was on the lift and at a comfortable working height too. The support wants to be very reliable and secure. At the dealer there's no risk but at home, have an excited dog run into the support and knock it out from under the car....there could be expensive repercussions. Oh, I took my Turbo out the other day and after the drive train was fully up to operating temp I managed to get a bit of a clunk (not that bad though, thank goodness) by in 1st or 2nd accelerating the car up to around 2K and then quickly releasing the gas pedal, then reasonably quickly again pressing down on the pedal. The knock is I suspect arises from the clearances that are present. I never drive my car this way though on purpose, save this time of course, but once in a great while while I just get just sloppy with the clutch/pedal and hear a faint clunk from I suspect the drive train gear lash. As I was driving the car before and during and after this I was thinking to myself that I strive -- it comes almost second nature to me I guess for I do not think I consciously think about this constantly while driving -- to be gentle/smooth with the car and its controls. Sincerely, Macster.

just throwing this out there, but loose drop links and sway bars can cause clunking from stop to moving... simple to just tug on the links and bars for the hell of it.

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Thanks for abusing your car Macster in the pursuit of trying to help me!! Your experience is almost exactly like mine. Since conversing with you guys I've been changing gear further up the range.....3k and above.....99% no clunks when doing this and I think the remaining 1% is likely due to my being overly sensitised to it and perhaps hearing things that under any other circumstances, I would not. Once again people, I sincerely do appreciate your help and indulgence of this newbie. Best Regards Les.

One other thing that can give a clunk is a worn/deteriorating trans mount. You would get that clunk every time you let up on the gas and stepped on it again. Not just on gear changes.

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I wondered about that too, but the dealer said they checked and all was in order. Thanks for the input! Les.