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986 02 Gearbox problem - 2nd gear grinding


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Hello all,

My 02 986S has some problem with the gearbox since yesterday. I get some grinding from 1st to 2nd, or 3rd to 2nd, especially when car is cold. I can't get second gear most of the times. The problem goes away when engine gets hot.

Is it a synchro issue ? Can this be repaired, or I need a new box ???

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Hello all,

My 02 986S has some problem with the gearbox since yesterday. I get some grinding from 1st to 2nd, or 3rd to 2nd, especially when car is cold. I can't get second gear most of the times. The problem goes away when engine gets hot.

Is it a synchro issue ? Can this be repaired, or I need a new box ???

My 2 cents: In that it happened in 2 gears and overnight (pretty remarkable if it was your box unless you were really romping on it), it must be something systemic. Your clutch probably isn’t disengaging or you dumped all your gearbox oil (unlikely).

Good luck, PK

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Well since it seems you're only having problems with going into second, I would guess your second gear syncho teeth are worn along with the syncro guide sleeve for first and second. The good news is parts are now available to fix these (in the US at least) so you wont need a new whole new gear box. You're probably going to have to remove the gearbox and inspect the clutch and if everything is good there inspect the gearset.

For what its worth, the last time I saw this problem it was a shredded second gear.

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Well since it seems you're only having problems with going into second, I would guess your second gear syncho teeth are worn along with the syncro guide sleeve for first and second. The good news is parts are now available to fix these (in the US at least) so you wont need a new whole new gear box. You're probably going to have to remove the gearbox and inspect the clutch and if everything is good there inspect the gearset.

For what its worth, the last time I saw this problem it was a shredded second gear.

Hi, are you saying sycros can be replaced without a complete rebuild? My second is shot, 3rd is weak and first (status unknown) I couldn’t care less about.

Did you imply this could be done with just the gear box removed?? DYI?? (I’m pretty seasoned…rebuilt around 12 motors in my life including a 928) Or $$$ guesstimate?

Aside from grinding 2nd without dbl clutching, and a bit of grinding in 3rd nothing howls, clutch works fine etc. Pretty low miles to boot.

What’s the minimum you think I could get away with?

Regards, PK

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Well since it seems you're only having problems with going into second, I would guess your second gear syncho teeth are worn along with the syncro guide sleeve for first and second. The good news is parts are now available to fix these (in the US at least) so you wont need a new whole new gear box. You're probably going to have to remove the gearbox and inspect the clutch and if everything is good there inspect the gearset.

For what its worth, the last time I saw this problem it was a shredded second gear.

Hi, are you saying sycros can be replaced without a complete rebuild? My second is shot, 3rd is weak and first (status unknown) I couldn’t care less about.

Did you imply this could be done with just the gear box removed?? DYI?? (I’m pretty seasoned…rebuilt around 12 motors in my life including a 928) Or $$$ guesstimate?

Aside from grinding 2nd without dbl clutching, and a bit of grinding in 3rd nothing howls, clutch works fine etc. Pretty low miles to boot.

What’s the minimum you think I could get away with?

Regards, PK

Technically yes the synchro parts can be replaced individually. Whether or not you could get away with that depends on what you find when you open the gearbox up and inspect. It seems like usually by the time you experience a problem the damage is already done so I would bet you're in for more than just the synchros. There is likely damage to the synchro teeth on your gears and if you have to replace the loose gear wheels for first and second, Porsche requires replacement of the corresponding fixed gears if the milage is above something around 15k. So I would guess you're in for replacing first, second, the entire synchro assembly and if you wanted to comply with the Porsche's guidelines, the input shaft. Thats not taking into account whatever you find wrong with third.

You can remove only the gearbox by itself, so the engine can stay in the car. I'm actually not familiar with rebuilding G86.01 boxes, I've only ever rebuilt the G86.20s. It would be a serious DYI. I know the G86.20 box would be pretty much impossible to do DYI due to all of the special press tools needed. I think if you want to save money on this you would be better off removing the gearbox yourself and then taking it to the dealer.

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Well since it seems you're only having problems with going into second, I would guess your second gear syncho teeth are worn along with the syncro guide sleeve for first and second. The good news is parts are now available to fix these (in the US at least) so you wont need a new whole new gear box. You're probably going to have to remove the gearbox and inspect the clutch and if everything is good there inspect the gearset.

For what its worth, the last time I saw this problem it was a shredded second gear.

Hi, are you saying sycros can be replaced without a complete rebuild? My second is shot, 3rd is weak and first (status unknown) I couldn’t care less about.

Did you imply this could be done with just the gear box removed?? DYI?? (I’m pretty seasoned…rebuilt around 12 motors in my life including a 928) Or $$$ guesstimate?

Aside from grinding 2nd without dbl clutching, and a bit of grinding in 3rd nothing howls, clutch works fine etc. Pretty low miles to boot.

What’s the minimum you think I could get away with?

Regards, PK

... It seems like usually by the time you experience a problem the damage is already done so I would bet you're in for more than just the synchros. There is likely damage to the synchro teeth on your gears and if you have to replace the loose gear wheels for first and second, Porsche requires replacement of the corresponding fixed gears if the milage is above something around 15k. So I would guess you're in for replacing first, second, the entire synchro assembly and if you wanted to comply with the Porsche's guidelines, the input shaft. ...

You can remove only the gearbox by itself, so the engine can stay in the car. ...pretty much impossible to do DYI due to all of the special press tools needed. I think if you want to save money on this you would be better off removing the gearbox yourself and then taking it to the dealer.

Hello,

Thanks for your reply, finding someone who’s got there hands dirty in a gear box is just the person I wanted to. I’ve done lots of motors, never a trans.

Isn’t the damage just the replaceable synchros most of the time?

I’ve Haven’t really been cramming the thing into gear. Doing my best double clutching I can usually get it into second with minimal or no gnashing, 3rd only grinds with a high rev. fast shift. (there’s no howls and the like) How likely Is it that I’ve damaged more than the synchros?

If you talk me out of DIYing it, I’d probably be taking it to an competent indi. shop I use. I’m a bit critical about dealerships in general and specifically Porsche, I think they overcharge and over prescribe, not to mention the fact that the a large percentage of a dealers profit comes from the service bays’

That would be nice, do you mean just the gear box or the whole transaxle assem?

I’ve access to a 20 ton press and a Lath and mill to fabricate tools, but if that’s a hug program in it self…I’d probably pass.

How do you feel about junkyard Trans? There’s several on Ebay (from a yard I trust) for $1500,supposedly with 37k miles, Their guaranteed for 3 months. If it’s good for 3 months, driven modestly and not often, any idea the likely the useful life expectancy?

Thanks, PK

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Well since it seems you're only having problems with going into second, I would guess your second gear syncho teeth are worn along with the syncro guide sleeve for first and second. The good news is parts are now available to fix these (in the US at least) so you wont need a new whole new gear box. You're probably going to have to remove the gearbox and inspect the clutch and if everything is good there inspect the gearset.

For what its worth, the last time I saw this problem it was a shredded second gear.

Hi, are you saying sycros can be replaced without a complete rebuild? My second is shot, 3rd is weak and first (status unknown) I couldn’t care less about.

Did you imply this could be done with just the gear box removed?? DYI?? (I’m pretty seasoned…rebuilt around 12 motors in my life including a 928) Or $$$ guesstimate?

Aside from grinding 2nd without dbl clutching, and a bit of grinding in 3rd nothing howls, clutch works fine etc. Pretty low miles to boot.

What’s the minimum you think I could get away with?

Regards, PK

... It seems like usually by the time you experience a problem the damage is already done so I would bet you're in for more than just the synchros. There is likely damage to the synchro teeth on your gears and if you have to replace the loose gear wheels for first and second, Porsche requires replacement of the corresponding fixed gears if the milage is above something around 15k. So I would guess you're in for replacing first, second, the entire synchro assembly and if you wanted to comply with the Porsche's guidelines, the input shaft. ...

You can remove only the gearbox by itself, so the engine can stay in the car. ...pretty much impossible to do DYI due to all of the special press tools needed. I think if you want to save money on this you would be better off removing the gearbox yourself and then taking it to the dealer.

Hello,

Thanks for your reply, finding someone who’s got there hands dirty in a gear box is just the person I wanted to. I’ve done lots of motors, never a trans.

Isn’t the damage just the replaceable synchros most of the time?

I’ve Haven’t really been cramming the thing into gear. Doing my best double clutching I can usually get it into second with minimal or no gnashing, 3rd only grinds with a high rev. fast shift. (there’s no howls and the like) How likely Is it that I’ve damaged more than the synchros?

If you talk me out of DIYing it, I’d probably be taking it to an competent indi. shop I use. I’m a bit critical about dealerships in general and specifically Porsche, I think they overcharge and over prescribe, not to mention the fact that the a large percentage of a dealers profit comes from the service bays’

That would be nice, do you mean just the gear box or the whole transaxle assem?

I’ve access to a 20 ton press and a Lath and mill to fabricate tools, but if that’s a hug program in it self…I’d probably pass.

How do you feel about junkyard Trans? There’s several on Ebay (from a yard I trust) for $1500,supposedly with 37k miles, Their guaranteed for 3 months. If it’s good for 3 months, driven modestly and not often, any idea the likely the useful life expectancy?

Thanks, PK

You really never know the extent of the damage until you have a look for yourself. When you hear the grinding noise its not the synchro rings making the noise, its the guide sleeve of the synchro assembly and the synchro teeth on the gear wheel that are grinding each other. When these teeth get rounded off you have all sorts of problems. Say the synchro teeth on the second gear wheel were rounded, you could put a whole new synchro and rings in and you would still grind and likely jump out of gear too. I would say at this point its pretty likely there is more damage than just the synchro, but hey I lost my X ray glasses so you really need to tear the cover off and inspect it to know for sure.

I think you have your terminology a bit skewed, the gearbox is the transaxle. They are one and the same in rear/mid engined Porsches. Also dealer profits come from selling cars and selling parts. Actual profits from repair work performed is smaller than you think. Dealership service overhead is huge. Actually the entire "service" side of the business is looked upon as a necessary nuisance. The main reason dealers have service departments is because you cant sell cars without having a place to fix the inevitable broken ones.

A junkyard gearbox is definitely an option. Theres no real way to give any reasonable estimate on life expectancy on a junkyard box. You have no idea whats inside or whose been rowing the gears for the last 37k miles. As for myself the cost savings wouldn't be worth the lost peace of mind. On the last G86.20 I rebuilt there was a bit over 2 grand in parts (mostly because its needed a new input shaft). A brand new G86.20 with full Porsche parts warranty (2 years/unlimited mileage) was 4400. So yeah the junkyard box is an option but its rolling the dice for sure.

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You really never know the extent of the damage until you have a look for yourself. When you hear the grinding noise its not the synchro rings making the noise, its the guide sleeve of the synchro assembly and the synchro teeth on the gear wheel that are grinding each other. When these teeth get rounded off you have all sorts of problems. Say the synchro teeth on the second gear wheel were rounded, you could put a whole new synchro and rings in and you would still grind and likely jump out of gear too. I would say at this point its pretty likely there is more damage than just the synchro, but hey I lost my X ray glasses so you really need to tear the cover off and inspect it to know for sure.

I think you have your terminology a bit skewed, the gearbox is the transaxle. They are one and the same in rear/mid engined Porsches. Also dealer profits come from selling cars and selling parts. Actual profits from repair work performed is smaller than you think. Dealership service overhead is huge. Actually the entire "service" side of the business is looked upon as a necessary nuisance. The main reason dealers have service departments is because you cant sell cars without having a place to fix the inevitable broken ones.

A junkyard gearbox is definitely an option. Theres no real way to give any reasonable estimate on life expectancy on a junkyard box. You have no idea whats inside or whose been rowing the gears for the last 37k miles. As for myself the cost savings wouldn't be worth the lost peace of mind. On the last G86.20 I rebuilt there was a bit over 2 grand in parts (mostly because its needed a new input shaft). A brand new G86.20 with full Porsche parts warranty (2 years/unlimited mileage) was 4400. So yeah the junkyard box is an option but its rolling the dice for sure.

THanks for the education

I guess I’m unsold on the DIY route. Transmissions always seem like something really scary and I felt psyched. My logic, it seems new, rebuilt, whatever, motors are always more expensive than transmissions. If it’s cheaper, It must be simpler and Motors don’t confuse me at all. So...

2 yr. warranty is great. Would have never guessed. My BMW trans gave out a while back. The dealer offered 3 or 6 months for a new or factory rebuilt trans. An indie gave me 2 yrs 24k warranty. That was about 6 yrs. Ago, no probs.

The gearbox/ transaxle confusion: my book shows the box with all the gears in it separated from the differential & bell housing. Thought it would be nice not to have to disconnect the axels & what not. Just shuffle that little box with all the gears in it (didn’t say “gear-box”) across town.

As for the dealerships profit center, a high school buddy’s family owned a dealership, There profit was skewed toward service end (and the parts for the service)…but then again, theirs was a Buick dealership…

The extent of the damage, I see your point and you’ve been there and I haven’t. I guess my only reason for optimism as to the extent of the damage is that gnashing progressed from miner to major with me at the wheel and I sure as _ell wasn’t driving around crashing through the gears

The junkyard route, true, not much piece of mind, they wraped it around a tree. I guess I just don’t have a good feel for how quickly a trans can degenerate. Would abuse of a good and working trans just show it's with a bang?

Anyway thanks, probably go with a rebuild from my fav.shop …

PK

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PK2,

I have never been inside a Porsche gearbox but I have had some experience with Toyota/Nissan. I own a service business and for 30 yrs our guys ran around in a fleet of mini trucks with 5spds. As you can imagine with 50 stops a day they were brutal on clutches and 2nd gear synchros. If a trans started to go south we would drain and inspect the gear oil. If the oil still had good color and very little metal flakes (rare) it was worth rebuilding with a good life ahead. If it looked bad and was full of flakes, chunks, bits o synchro etc. It was replaced with a junkyard trans that had good clean gear oil. We probably changed out 15 or so over the years and we have never had a bad experience with a junkyard trans with good clean oil.

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