DMF, Clutch, TOB symptoms. Opinons?

Hi all, So I've been experiencing some issues with my flywheel, clutch, throwout bearing recently and wanted to run my diagnostics by you all before I purchase parts and drop the tranny... A tad bit of background info: 2002 carrera 2, 77k miles, 6-speed manual (G96/03), one owner before me, took perfect care of the car always serviced at Porsche Center. It's in great shape inside out. I've had it for 6 months and about 4k miles and have been doing all maintenance on it myself so far. I don't have any receipts of what has been done on the car exactly throughout it's life but service manual has been stamped for all minion, major maintenance, airbags and the rest. Ok, now for he fun bit with symptom descriptions.... in order of their manifestation. 1) Rattle under rear of car when engine is turned off, just at the end of it's spool down with clutch depressed and car in neutral. Will NOT rattle if clutch is engaged and car is in neutral. 2) I noticed that when cruising with lower rpm's with barely any throttle input, if I let up on the throttle to zero input, there would be a dull "clunk" sound from the rear of the car when the the power transferred. (easily amplified by driving on a road with a wall close to it fr the sound to bounce off of) I've read the small amount of posts that list this symptom but none have the OP's solution/aftermath of what happened.The same would happen if in same situation where cruising with zero input from accelerator pedal, I give it a bit of gas, sen the slightest amount, the dull "clunk" will happen. This goes for all gears I think (definitely 3rd 4th 5th 6th) (higher rpm's override the sound I think) 3) Started getting a "squeaking" sound when clutch was in mouvement (either pressing down on pedal or releasing back up) under the rear. Break---------------------------------------------------------------------------Break At this point in the story, I installed Function First engine mounts (mine were OE and tired) as well as the Function First transmission mounts (black 80a rating) with no hics whatsoever. I also replaced the transmission fluid with Mobil 1 75W-90. all ok. Noticed some new NVH over stock, but it was expected. Nothing beyond my moral scope of acceptance of how the car is supposed to feel and drive. End of break--------------------------------------------------------------End of break 4) If I am manoeuvring in a parking lot or driving in bumper to bumper traffic (forward or reverse) the following happens. standstill -> clutch in -> engage first gear (sometimes a random "clunk") -> clutch out with gas to start moving ->bumper to bumper traffic so clutch back in -> still rolling (coasting) ->re engage 1st or 2nd gear (both the same effect) -> when re engaging the clutch, the "Clunk" turns into a dull "multi clunk" or "rattle" or "chatter". ******In the video at the bottom you can hear this at 5 and again at 6 seconds when I am depressing and releasing the clutch in 2nd gear while rolling. (sound isn't great, a little bit to metallic, it's a bit more dull in reality)****** 5) I also found that to replicate, with the car started, handbrake on, in neutral, if I engage the clutch and then proceed to "Dump" it (release it quickly) with no gear engaged (still in neutral) the "clunk" happens. Tried this coasting down a hill in neutral today and surprisingly fades when the car starts rolling at 5MPH and disappears completely at 15mph... *******Diagnostics******** - I'm fairly sure the flywheel (I'm supposing it's stock DMF as I don't have the records of a change) has broken a spring or springs. - I'm not to sure what a failing or used TOB sounds like but will replace it when tranny is out as well. - There has been NO clutch slip and NO change in feeling of the clutch pedal/clutch play at all. - I have done 2nd gear starts and everything is good. - I have not noticed any real change depending on cold or up to temp engine/gearbox. - I do not have a 2nd gear pop out problem. - There is no sporadic or (other than the symptoms described) strange behaviour from the engine/gearbox/clutch I'm looking at the complete clutch/DMF/TOB kit from pelicanparts and will install myself over the coming weeks, and will probably do RMS while I'm in there. For those who will ask, I do not know if the IMS has been done or not. I have done 2 oil changes myself and have had no shavings in the filter upon inspection and chose to stay away from that vortex for the moment. I will of course inspect for leaks when I'm in there and go from there. My question I guess is: does this all sound correct to you? Thanks in advance for reading my new detective novel I have just wrote especially for you all here at Rennlist... DMF rattle 996 - YouTube

Before you pull the trans check the transmission mount for wear/play. https://rennlist.com/forums/996-foru...-accuracy.html or diy: https://rennlist.com/forums/996-foru...-fill-diy.html

I just installed the function first transmission inserts 2 weeks ago and the transmission mount was in good shape. Fairly sure it was replaced by PO not too long ago. The insert went in pretty easily and upon visual inspection was in good shape and was not torn or sagging. I'll double check all bolts and torque this week just to be sure but pretty sure it's not the upper, lower mounts or the mount itself that could be loose. i'll post back results asap.

Missed that you did the Trans mounts. Sounds like your DMF may have too much play. Just a note, even a new DMF can make rattle noises when you shut down with the clutch disengaged or lug the engine. DMF test: 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 (0.590”), 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

I have the same issue with 2000 C2. It makes that exact noise in your video when engaging the clutch in reverse, and 1st gear. It gets worse as the car warms up. Both clutch/flywheel were replaced about 3k miles ago, and both the previous and new clutch/flywheel combos made this noise. My indy says it's normal. I've found the rattle can be corrected by adding more gas on takeoff. What is your opinion of the F1st transmission mounts?

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Thanks fpb, I've seen this TSB in my searches and will definitely proceed to check the flywheel while i'm in there but will probably have the pieces ordered and on hand since "I'm in there"... I'll keep you posted once I have the transmission off. Probably in 2 weeks time.

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Adam, I can see the logic behind the "not enough gas on takeoff" slapping the DMF in both 1st and reverse. I've been able to correct as well but still not sure if this is "normal" (possibly not coming from the flywheel or clutch.) Did you have the throwout bearing changed when the DMF/clutch was done? (I'm guessing that yes it was) Do you have any "thuds" or "clanks" when mass transfer happens slight acceleration while coasting or letting off the gas completely while in higher gears (4th, 5th) when going about 30mph? I'm pretty sure that I'm dealing with multiple issues here that are coming from different elements in the engine, transmission, and possibly suspension or other mounts... Concerning the F1st mounts, I'm happy with the full setup I purchased from them, being transmission inserts and engine mounts. I did not however try them out separately and my engine mounts were on their last leg... I might recommend trying the 70a Yellow mounts for a bit less NVH but that boils down to personal levels of acceptance... Luka at F1st also said something very important in a post he wrote concerning the inserts, it read something along the lines of : Some people will have more vibration than others because underlying issues withe the vehicle can/will be amplified. I pretty sure that I have some extra NVH from other issues with my engine/transmission/other that I can now track down a bit more easily. But the car feels very solid now in the rear. I had a lot of lateral and forward/backwards engine/transmission mass transfer that the engine mounts and inserts cleared up. I would recommend their products for the immediate chafe they bring to the car but can't speak about long term durability yet. That being said, Luka is very present on RL and that helps in believing any problems will be dealt with in good fashion. Thanks for sharing your symptoms and good luck/.

I would assume the throwout bearing was replaced, as that's part of most OEM kits. Thuds and clanks used to occur before the flywheel/clutch were replaced. Indy suspected a warped flywheel. After the repair, there is still a very noticeable weight transfer at speeds over 40mph (unnoticeable below 40mph), but no thuds or clanks. Indy also recommended a new slave cylinder in case that was contributing the not so smooth shifting dynamics I was experiencing at the time. I'm very interested to see how your project turns out. Good luck. Yes, I've been thinking about the 70a yellow transmission and engine mounts. Is it necessary to drop the transmission for these?

Thanks for the input../ I'm pretty sure I have other issues that create the clank during weight transfer. From all the posts I've seen, I haven't come across anyone that has solved this problem.. Looks like it's time to put on the inspector gadget trench coat and hat and get to it... I'll keep you posted. No need to drop the transmission. F1st has a great DIY on their website to get them in. Not difficult at all if you know how to turn a wrench and take your time. Jack the car up, remove plastic panels on underbody, support transmission with floor jack and unbolt lower and upper transmission mounts, remove bolts, place inserts and put everything back after.. It takes a bit of wiggling around with the lower and upper but it's not bad. Torque all bolts to 65nm and you're good to go. If you want to do it, read through their diy (has nice pics) and if you need more help just help, I can walk you through it. If you have a lot of weight transfer though and you engine mounts are old as well, the math is easy, the entire engine and transmission is bolted to the chassis in 3 places, 2 engine mounts and 1 transmission. I'd do the engine mounts first. Much easier to swap out as well. Great upgrade for few $$. Keep us posted what you end up doing. Ps: as people say this often, no affiliation with F1st... Just a a happy customer..

If emanating from under the dash, the clutch squeak is just the assist spring. Nothing to worry about. If the squeak is coming from under the car, there's a thread for that: https://rennlist.com/forums/996-foru...tml?styleid=13

Sounds like a pressure plate issue. Had the same sound on my 6. Mike

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I completely missed these answers, my bad... 5CHN3LL, Thanks for the input, this is definitely coming from under the car at trans/engine. Also is clutch actuated. I still haven't had time to take care of it but will report back as soon as I have found the source. Right now it's 105�f at 12h so all garage work is pretty much impossible without loosing 20lbs. Thanks Mike as well. While I'm in there everything listed in the title will be done and then some. I'll keep you posted as soon as I'm done...

Hey guys, I'm back with an update.. I dropped the transmission about 3 months ago to replace DMF, clutch, throw out bearing and tube etc... I ordered the updated 997 clutch fork assembly and put a new RMS on. All went well. started the car.... and...... no change at all... :banged: I was expecting it though. As soon as I had access to the flywheel, I tested it for excess spin and found none. Everything was in pretty good shape. My clutch feel was much better though. Smoother and lighter clutch now, so at least theres that. And peace of mind... That being said I have been tracking noises for the past 3 months and have narrowed it down to the main shaft and secondary shaft bearings in the transmission... When load is applied or released from the main shaft the transmission shutters.. also probably the clunking when shutting off the engine while clutched depressed. There has been a sort of whooshing mechanical sound as well while idling with clutch depressed that disappears when the clutch is engaged. I'm sure that some amount of noise is normal especially with the stiffer transmission mount and increased NVH int he cabin but it seems to be a little much along with the other symptoms.. In the video below you can hear the exact type of sound at the 1:42 mark. I'm going to do another transmission oil change pretty soon here and give the Porsche transmission fluid it's chance and see how it does. I'll be looking for the magic silver grease on the magnet this time. If there is a bunch under there I'll pop the nose cone and see whats up on the inside... If it's all there, I'll be looking at a rebuild probably, but that will be another thread.. That's all for now...