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987.2 Clutch/Transmission issue-

1963 Views 47 Replies 9 Participants Last post by  RSchwerer
I'm a long time lurker, first time posting here and I could use some help with an intermittent 1st and 2nd trans grind when cold.

History:
I've got a 2010 Cayman 2.9l with the 6 speed with 37k miles, I bought it 8 years ago with 4k miles. 4 years ago the shift cables snapped and I brought it to my indy shop who replaced the cables and changed the trans fluid and the clutch fluid. The past 4 years I haven't driven it all that much, about 12k miles. Sometimes the car sits for a few weeks, but no longer than a month.

Issues:
In the past 2 years (about 5k miles ago) I started noticing a squeaking sound when the clutch petal was slowly depressed, no other symptoms.

3 months ago I started her up and it would not go into 1st or 2nd gear, but it went into all other gears fine. After 5 mins of running in the garage, i tried holding the shifter towards 2nd and it finally started to slide into 2nd gear and then I was able to get it in 1st. It seemed ok after that so I drove it around the block and got it up to operating temp. The next day when I went out for a drive it did the same thing.

Diagnosis:

I called my local indy shop and they suggested i tow it in. They had the car for about a week and they said they found no issues with it other than a slight grind in 2nd which happened a few times over test driving it and spending a few hours looking it over. They couldn't replicate the issue since it only happens when it's cold, they said that i just have to push harder into gear and it sometimes happens when these cars age. They changed the trans fluid and said the clutch fluid was fine. I went to pick it up and the engine was cold so it was doing the same thing. This time i pushed hard and it went into 1st and 2nd. The squeaking noise disappeared but the clutch has a weird springy binding sensation when you push it in slowly.

Yesterday I went to start it and it seemed worse. The car was on level ground in my garage, when started in neutral and cold, depressed the clutch and moved the shifter towards 1st, I had a sensation the car moved forward before i even put it in gear (as if someone was rocking the car from behind). For the first 3 miles it was very inconsistent, there was a slight grind when forcing it in 1st and 2nd but not all the time. As the car warmed up it drove completely fine.

This morning it did the same thing, but this time I noticed that sensation of the car moving forward was so bad that the car started to roll down out of the garage, over a rubber door seal I have on the garage floor and down the driveway without me even releasing the clutch or putting it in 1st.

Since the car drives fine when warm, I feel like I'll get the same response from the Indy shop. Does anyone have any suggestions on how to handle this or have had issues like this?

Thank you
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That is a good point. The shop changed the trans fluid 200 mi ago. I assumed they added it correctly but it wouldn't hurt to check. I think I'll do that over the weekend.

I spoke to my buddy who's a Porsche mechanic. Based on the summary above, he said the trans needs to come out to inspect the clutch assembly. He suspects a defect or cracked pressure plate, hence the intermittent issues described above. If there is nothing worn in the clutch assembly then the transmission is the culprit.

Porsche does not service transmissions, they just replace them馃ズ.

He gave me the name of a reputable shop owner in Santa Monica who I will call in the morning to discuss the next steps.
Sounds like a decent mechanic..

I said about a week ago:
the OP also said "The squeaking noise disappeared but the clutch has a weird springy binding sensation when you push it in slowly. " - that rather obviously indicates some issue with the clutch releasing. A bad pressure plate? A warped clutch disk? A bad slave cylinder? Lots of possibilities, just needs someone who knows what they're looking at to sort it out.
I'm surprised he didn't mention a warped clutch disk, that isn't really uncommon.. and has the same effect as a warped pressure plate.
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Did the original shop ever change the transmission oil? (You mentioned it in the original post, but it's not clear when they did this.) If so - is there any record of what they used? As a general point - use of GL5 oils is not encouraged in transmissions. Most GL5 oils have a large dose of sulphur in them that will eat up the syncro's. It might also cause the symptoms you're seeing. Given the incompetence shown by the shop already it wouldn't surprise me at all if they put the wrong oil in. What should be in there is GL4 oil. Ask your friend what oil his Porsche dealership uses when they change transmission oil, and you might want to consider a DIY on changing it.
I want to correct this ancient bit of misinformation that gets repeated ad infinitum on the Internet. GL-5 fluids are fine, and in fact Porsche issued a TSB in 1988 stating that "Transmission oil labeled API Service Classification GL 5 or MIL-L 2105 B must be used on all Porsche models," their bulletin 8813. The issue with the chemistry of really early GL-5 fluids was resolved a long time ago.

Porsche does not offer service parts, tools, or technical information, and their dealership techs will not service the transmissions except to change the fluid and replace seals. Despite that, a few indepedent transmission specialists have figured out how to service and repair them. I'm one of them. Porsche will of course be happy to sell you a remanufactured transmission.

Do not use ATF in your transmission, unless you want to hasten its demise! Use a quality 75W90 manual transmission fluid such as Mobil 1 LS 75W90, Motul 300 75W90, or Porsche or Audi's branded fluid.

Another possible cause for your clutch to drag is air in the clutch hydraulics. A positive-pressure bleed would help purge air from the system. Could be a bad master or slave cylinder as well. Good luck,
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Do not use ATF in your transmission, unless you want to hasten its demise! Use a quality 75W90 manual transmission fluid such as Mobil 1 LS 75W90, Motul 300 75W90, or Porsche or Audi's branded fluid.

Another possible cause for your clutch to drag is air in the clutch hydraulics. A positive-pressure bleed would help purge air from the system. Could be a bad master or slave cylinder as well. Good luck,
Hi Kevin, good to have an authoritative voice speaking up...

What's the issue with ATF in a manual transmission? I seem to recall some manual transmissions actually called for ATF. It would seem the needs of the two would be very similar. Gear and bearing lubrication. In the automatic - the fluid has to work with the friction clutches, in the manual, it would have to work with the synchronizer rings. What issues have you seen? My experience with it in the 1983 Toyota Supra was it solved a lubrication problem, where I got an awful-sounding squeal with a cold transmission on the 1st-2nd gear shift. My mechanic thought that it might be the transmission fluid drained down off a component - and using ATF the lanolin in it stayed in place better. Whatever - it was quiet and smooth shifting for the rest of the time I owned it.

On GL5 vs GL4 - I tend to be cautious. I once owned a BMW M3 E46 with the ZF 6-speed manual transmission. It was a balky shifter when cold, so I thought perhaps changing the oil might help, and I used a 75W90 GL5 oil. From being balky (mostly in the initial 1-2 shift) it went to be difficult to get into any gear when upshifting, cold or hot. It stayed in the transmission for about an hour, and then I drained it out and went back to a GL4 and all was well... That was a Valvoline non-synthetic GL5 at the time. I think I still have that bottle kicking around somewhere. Obviously, things have changed, and better oils are available now.

I believe he had the clutch slave cylinder replaced somewhere in the saga of what's been done - to no good effect. One would hope the shop could bleed the clutch circuit (which could almost be done by gravity - but pressure bleed sometimes breaks free air bubbles..) but given their other errors in diagnosis, I wouldn't take this for certain.
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Of course, I agree with the clutch/pressure plate inspection. I figure that's where the problem is. I would recommend getting a replacement one as you might as well replace it while you're in there even if it looks fine.
What's the issue with ATF in a manual transmission? I seem to recall some manual transmissions actually called for ATF. It would seem the needs of the two would be very similar. Gear and bearing lubrication. In the automatic - the fluid has to work with the friction clutches, in the manual, it would have to work with the synchronizer rings. What issues have you seen? My experience with it in the 1983 Toyota Supra was it solved a lubrication problem, where I got an awful-sounding squeal with a cold transmission on the 1st-2nd gear shift. My mechanic thought that it might be the transmission fluid drained down off a component - and using ATF the lanolin in it stayed in place better. Whatever - it was quiet and smooth shifting for the rest of the time I owned it.
I'm not a lubrication scientist or engineer and so cannot give a very deep answer. Different viscosity, different base chemistry, additives, etc. Yes, some manual transmissions have been designed for ATF: I owned a Mercedes 190E2.3-16 that used ATF in its manual transmission. They key notion here is that they were designed for ATF.

If you use a different type of fluid, or a heavier grade (eg, 75W140) and it appears to "solve" the problem, chances are that it's just hidden the problem at the expensive of accelerated wear and damage to parts of the transmission that were designed and tested for the original fluid. If you were running a marathon, and you sprained your ankle at mile 10, would you pop a few pain killers and finish the race? I hope not. But it is a fair analogy to what is likely happening with a variant fluid in a transmission that shows issues with the designed-for fluid. Cheers,
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If you use a different type of fluid, or a heavier grade (eg, 75W140) and it appears to "solve" the problem, chances are that it's just hidden the problem at the expensive of accelerated wear and damage to parts of the transmission that were designed and tested for the original fluid. If you were running a marathon, and you sprained your ankle at mile 10, would you pop a few pain killers and finish the race? I hope not. But it is a fair analogy to what is likely happening with a variant fluid in a transmission that shows issues with the designed-for fluid. Cheers,
No - I don't think that's a good analogy really. The analogy would be closer if the runner sprained his ankle, and was given the choice of finishing the race with aspirin or finishing the race without aspirin and with the ankle still causing pain, or being shot right there (as one does with horses..)

That was the decision on the Supra. It wasn't worth sinking money into rebuilding the transmission at that point, and the changed oil let it continue to be useful, despite having whatever was causing the noise still wrong with it (ie - sprained ankle and aspirin.) We really don't know if using the ATF caused any other damage to the transmission because the car was sold without any additional transmission problems taking place. It was sold locally, and I did see the car out and around for several years after that, so I'm guessing the ATF continued to work OK. It had enough rust on it that I can't imagine anyone would bother replacing or rebuilding the transmission if it failed.

I think at this point - certainly, all signs point to a dragging clutch, and I'd have to believe tracking that down is going to be the solution to the issue. And he should do a drain/fill of the transmission with factory-approved fluid since the trans will be out of the car anyway.
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Two things I鈥檓 getting out of this discussion: I agree with 鈥榮chwinn鈥 here about checking the clutch/pressure plate, maybe even a warped or deformed flywheel. And secondly, I would NOT bring my car back to this mechanic. I wouldn鈥檛 trust him to put air in my tires.
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Two things I鈥檓 getting out of this discussion: I agree with 鈥榮chwinn鈥 here about checking the clutch/pressure plate, maybe even a warped or deformed flywheel. And secondly, I would NOT bring my car back to this mechanic. I wouldn鈥檛 trust him to put air in my tires.
The plot thickens, I looked through the records of the shop and they are not using oem fluids and I have no idea if they used an oe shifter cable revision, slave or what.

3/20/18 20,280 miles Transmission Fluid Changed - Motul Gear 300 75w90 synthetic
1/9/23 36,578 miles Transmission Fluid Changed - BG UltraGuard 75w90 and a BG Limited Slip gear oil Additive
2/8/23 36,680 miles Clutch Fluid Change and Slave Cylinder - used ATE Type 200 Supergold Fluid & what appears to be an OE Slave part #

I only have myself to blame, I should have just trusted the dealership to handle this. I should have more information on Tues/Wed once the new shop looks it over. They may want to flush all the BG snake oil out of the trans and see if that solves the problem.
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Good find. I don't think non-OEM is necessarily bad, but whatever it is should match the required specs... so it would be good to check. If it doesn't match, then that's a good lead on the matter. If the specs match (GL rating as well as anti-slip additives and weights), then it may not be the issue, and you could skip that step/cost. Of course, you could change it anyway if you really wanted to... but I'm of the belief that if the specs match then you should be fine.

Of course, a fluid change would be cheaper than the clutch work, but I really feel that's where the issue lies...
Good find. I don't think non-OEM is necessarily bad, but whatever it is should match the required specs... so it would be good to check. If it doesn't match, then that's a good lead on the matter. If the specs match (GL rating as well as anti-slip additives and weights), then it may not be the issue, and you could skip that step/cost. Of course, you could change it anyway if you really wanted to... but I'm of the belief that if the specs match then you should be fine.

Of course, a fluid change would be cheaper than the clutch work, but I really feel that's where the issue lies...
.


My sentiments exactly. It will be interesting to see what my new shop says when they start to dive in.
This change is REALLY worrisome: 1/9/23 36,578 miles Transmission Fluid Changed - BG UltraGuard 75w90 and a BG Limited Slip gear oil Additive

That has no place in your transmission unless you have a limited slip differential in it (unlikely but not impossible - it would be on your build sheet). Limited Slip "additives" make the gear oil more slippery. This might sound like a great thing, but it can reduce the effectiveness of synchronizers making the transmission harder to shift... which you have.

My suggestion - get that crap out of there.
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The limited slip additive is definitely a bad idea, and that can screw up synchronizer performance. Agree it should probably be drained and replaced.

That said, if the car's creeping forward with the clutch down then the transmission fluid and/or cables have nothing to do with the issue. Your clutch is dragging: either there's a hydraulic issue with the clutch release, or a mechanical issue with the clutch or pressure plate itself. If the clutch is dragging that'll definitely cause issues getting into gear as well.

Looks like they replaced the slave to try to solve the problem? Assuming they did that and bled it properly, then that suggests some issue with the clutch assembly.

I also agree that you should probably find a new mechanic!
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Update:

The shop owner had driven the car several times and can attest to the shifting issues as well as the intermittent clutch disengagement. They first requested my approval to remove the console so they can check the shifter cable alignment. He adjusted the shifter cables which are in good order now, the cables were improperly aligned in between 1st and 2nd gear. The previous shop had installed the cables 10k mi ago and assured me they were checked two months ago when i brought it in for this issue. He said the shifting has improved but the disengagement is still there. The trans fluid was at the proper level but I requested that he drain the BG Trans fluid and LSD additive (i don't have an LSD) to put OE fluid in the trans; it did not solve the disengagement issues.

The trans was dropped this morning and the clutch assembly was inspected. No smoking gun but when placed on the bench he could see the clutch disc is slightly warped, warped enough to cause the disengagement issue. The Flywheel is in very good condition and there are no hot spots. He noted the car was driven easy as everything looked to spec (other than the warped disc). The disc had quite a bit of meat left on it (I believe he said 1mm but don't quote me on that).

The plan is to get a new OE Porsche Clutch disc, PP, fork, bearing and to reuse the flywheel as is. Since the console is removed from the shifter cables, I decided to splurge and get the OEM GT3 shifter assembly with metal bushings.
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Welp, at least someone finally seems to have solved it. I figured you'd find something like that.

When the clutch pedal is down, the engine should be physically disconnected from the transmission. So if the clutch is working right there's absolutely no way for anything aft of the clutch (transmission, shifter assembly, shift cables, fluid, gears, synchros, whatever) to cause the car to creep with the clutch pedal down. Any competent mechanic should have understood that right off the bat, and honestly it's pretty disturbing that their first thought after verifying that symptom was "let's check the shift cables".

Is this the same shop as before? Because if what you're saying about their troubleshooting capabilities is accurate then you really need to find another shop. I'm purely shade-tree but apparently I'm a lot better than your guys!

Anyway, once isolated to the clutch then it's got to be either the hydraulic release mechanism or, failing that, the clutch assembly is f-ed in some way.
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Welp, at least someone finally seems to have solved it. I figured you'd find something like that.

When the clutch pedal is down, the engine should be physically disconnected from the transmission. So if the clutch is working right there's absolutely no way for anything aft of the clutch (transmission, shifter assembly, shift cables, fluid, gears, synchros, whatever) to cause the car to creep with the clutch pedal down. Any competent mechanic should have understood that right off the bat, and honestly it's pretty disturbing that their first thought after verifying that symptom was "let's check the shift cables".

Is this the same shop as before? Because if what you're saying about their troubleshooting capabilities is accurate then you really need to find another shop. I'm purely shade-tree but apparently I'm a lot better than your guys!

Anyway, once isolated to the clutch then it's got to be either the hydraulic release mechanism or, failing that, the clutch assembly is f-ed in some way.
Both shops worked the cables, the 1st shop who installed them 10k mi ago, never adjusted them properly.

The current mechanic told me that he knew there were 2 issues, one being the disengagement issues and second, something wrong with the cables.
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God news and thanks for the update
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The current mechanic told me that he knew there were 2 issues, one being the disengagement issues and second, something wrong with the cables.
Okay, that's better, I thought you were still at the first place, lol. As long as he didn't try to blame the latter on the former you're all right.
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Okay, that's better, I thought you were still at the first place, lol. As long as he didn't try to blame the latter on the former you're all right.
No blame games, it difficult to pin point how the disengagement issues started but it's pretty obvious the first shop who installed the cables are incompetent. When the first shop installed the cables, I had to go back because I was having issues with shifting. I had to go for a ride with them and show them what it was doing. They adjusted something and it seemed better.
I had an incident this morning that made me think of this thread. I am in the process of doing a brake job (pads & rotors followed by flush) on my 2010 Cayman 2.9L MT. The car is up on Quick Jack with wheels off. I just finished the last (left rear) wheel and wanted to test that the new wear sensors were all working, so I started the car and stepped away It was in neutral. I noticed the left rear hub/rotor was slowly spinning. That's what reminded me of this thread. The right rear was stationary. After double checking it was in neutral, I put a gloved hand on the rotor and easily stopped it. When I let go, it remained stationary, but with a slight nudge, it started moving again. Is this normal?

Oh, one other odd thing associated with the above. I was able to start the engine without getting in and pressing the clutch or brake. I assumed my clutch switch is faulty and don't think it is related to the rotation.
I had an incident this morning that made me think of this thread. I am in the process of doing a brake job (pads & rotors followed by flush) on my 2010 Cayman 2.9L MT. The car is up on Quick Jack with wheels off. I just finished the last (left rear) wheel and wanted to test that the new wear sensors were all working, so I started the car and stepped out. It was in neutral. I noticed the left rear rear hub/rotor as slowly spinning. That's what reminded me of this thread. The right rear was stationary. After double checking it was in neutral, I put a gloved hand on the rotor and easily stopped it. When I let go, it remain stationary, but with a slight nudge, it started again. Is this normal?

Oh, one other odd thing associated with the above. I was able to start the engine without getting in and pressing the clutch or brake. I assumed my clutch switch is faulty and don't think it is related to the rotation.
I would think the starting without a clutch issue is the switch.
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