So it's come to this: rebuilding my transmission 💸💸💸

Hi, all. It's transmission rebuild time and I have a couple of questions: 1) Who should I turn to for the rebuild? I've seen mention of GBox, Cog's Cogs, and California Motorsports, but I don't know of anyone who's dealt with them. Would be great if there was a source a little closer to Chicago of course. 2) As long as we're taking the transmission out, what else should I address? IMS was already done by the previous owner, so I'm thinking clutch, RMS, and a Wavetrac LSD. Thanks, everyone. If you need me, I'll be digging into my couch cushions looking for loose hundred dollar bills.

Out of the ones u have mentioned ONLY CMS. Do your research....i am in the middle of a g96 cup trans build and i have been talking to a lot of the shops. There is a current thread on gbox in the 6turbo board u may want to find. There is Carquip in CO. Not sure if they do regular carrara boxes but they have been around forever. I think Bill Rader (sp) may also do carrera trans too. https://billradermotorsports.com/

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I would give Eurosport (Bensonville) or Fischer (Barrington) a call. They may also rebuild them since they are both big club racing shops.

Lots of 6Turbo guys have had their G50 gearboxes rebuilt by CMS, myself included.

I like reading posts by @KevinGross about our transmissions. He seems to really know how to rebuild these.

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I met Kevin back in the 70's or early 80's when I lived close to him in western Mass. . Use to ski up north with some of his crew, might have even skied with Kevin, can't remember. Do remember they all were into Porsche and VW. One of his friends had a absolutely beautiful green Carmen Gia with a Porsche engine iirr... Wish I could remember his name, he use to walk around with a cane iirr from a ski racing accident... Kevin has been a Porsche wizard for a very very long time. I would 100% trust him with my tranny. If Kevin tells you something about your tranny you can believe it. That being said he probably isn't the cheapest company in town. But by all means talk to him, compare his prices/services to the other guys. I know they aren't cheap either. Not sure if they eat and breath Porsche for half a century like Kevin...

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Thank you for the kind words! Much appreciated.

I would vote Kevin Gross.

What happened to your transmission?

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Second gear's on its way out. From what I can tell, that's par for the course with an early dot-1 like mine around 110k miles.

Sounds like we're trending CMS and Kevin Gross. Thanks for the input, guys—appreciate it.

Is it whining? Not staying in gear? Thanks again.

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Not staying in gear. Second had already been popping out from stops/near-stops for a while complete with that awful crunching sound, but I learned to drive around it. Lately, though, it's started popping out once rolling now and again—crunching sound included—which seems like an indication that it's time to rebuild. This is what I imagine things look like: You Tube

Ahhhh, thanks.

Popping out when under load or just when off throttle?

Just for a bit of clarity, because I see mentions of Turbo and Cup transmissions here. The G96 street transmission is a different beast than the G50-based transmissions used in the GT2, 3, and Cup cars. The latter are an evolution of the G50 introduced for the MY87 911 Carrera. The G96 street transmission (G96.00, etc.) is more of a clean sheet of paper design, and it "features" (euphemism there) the interference-fit pinion shaft fixed gears requiring a 50-ton press to remove, and a bunch of heat and prayer to reinstall. They also have sealed double-row four-point contact bearings on the pinion and input shafts, same wonderful idea that endeared us to the M96 IMS bearing design (sarcasm this time). Fun facts: Porsche and Getrag used this same pinion shaft bearing in the G87.xx and G81.00 Cayman and Boxster transmissions. It was eventually replaced, first with an unsealed version of the double-row contact bearing. Later, in the GT4 boxes, they reverted to the paired design of a cylindrical roller and a single-row contact bearing, as used in the 915 and G50 transmissions. Unfortunately for us, those bearings were all made under contract by Schaeffler/INA/*** for Porsche, and Schaeffler will not sell them to anyone else as long as that contract is in effect.

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Under gentle-to-medium load�pulling away from a stop sign, or shifting into second just after pulling away.

seagull_cqx, do you have a short shifter installed?

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I do not! Regular ol' shifter for me.

That's pretty bad if it pops out under a load. Usually it's just on deceleration. Must be you are not getting full engagement.

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Yeah, it�s not great. The car�s still driveable�even in second most of the time�but the red flags are waving vigorously. But hey, hemorrhaging money is part of the Porsche experience.

Cms has some advantages and other may have too but i know they do it in house. They can repair the dog ring on the gear if its bad. This is important be cause the 1st and 2nd gears on your trans r machined into the main shaft. Im 99% u cant just swap the idler gear as they r "matched". A new input shaft and gears r $$$. They also make a bunch of upgraded parts so u dont have to wait for factory backorders. Hopefully its just a syncro package or worn a worn shift arrestor? Also the 1st and 2nd gear syncros r a special triple cone design and r about $800 per gear. Here is the 6th gear in my project cup trans. U can see the damaged dog ring. These r race gears and the dog ring is edm welded onto the gear so its not fixable. The nos gear set i found is $1k, new factory or from Guards is $1500-1800.

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Oh, I can absolutely see the wear on those teeth. I'll keep that in mind once my transmission is opened.

What kind of $$$ are we talking here for a rebuilt transmission? Is a second hand or salvaged transmission big bucks as well?

It depends on what u want ti do and who is building it. Again my refference is for the g50 mezger trans. There r 8 bearings and the dealer gets $550ish each. I have sourced the OE parts for less then half. Syncros (up to 7) the brass ones are around $300ea and if u go steel its $450 ish. Also shift forks can wear and then u can add a limited slip for $4k.. Labor is usually the cheapest part around $2-3k for a complete dissassebly and rebuild. Plus shipping. Bottom line is usually somewhere between $4-20k.

If you are replacing the transmission what are the advantages of a 997 Aisin over the g96? @KevinGross

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Unfortunately some m96 tranny bearings/parts are only available thru Porsche for big $$$. The non spline'd shafts that require high pressure pressed on gears/parts are not something the average garage will be able to do. This alone makes the 996 m96 trans expensive to build correctly From what I've seen, once trans gets worn enough that it won't stay in gear, a new sleeve and gear and syncro are needed at the least. All expensive parts. Then add in Porsche only bearings, this makes for an expensive difficult to rebuild tranny that needs to be done by an expert. I'd be surprised if you could get away for under $5K m96 trans is Not like the Mezger tranny at all.... It my limited m96 trans knowledge opinion the 996.2 tranny, less than but like the 997 tranny are slightly better stronger units than the 996.1 trans. 997 & to a lesser extent the 996.2 have some' upgraded internals. Maybe Kevin will chime in here, and share his wealth of trans expertise... jmo

The oddball split inner race pinion bearing is the tough one. Someone here found an Audi part that is identical for 1/5th the price Porsche gets. I did not write it down because I have a G50. Search around; there's several good G96 rebuild threads.

So when the price tag approaches $10,000, I think i will buy a new transmission from a dealer ... 99630002002, $12K. If you say please, they will take 10% off the price.

Should not cost anything like that. My buddy Jason (now perma-banned although no one knows why) had his trans rebuilt for the exact problem you have for about $3k.

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Where did he send his?

Look, if all you are gonna do is to pull the nose off, pull the second gear off, and replace the syncros and shift hub, it should not be too hard or expensive. $3k is probably right. However, these things will always have something else you want to do.

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If you're referring to the G97.01 transmission for normally aspirated cars, my experience is limited. Porsche and Aisin superseded everything in 1st through 3rd gears, the whole stack, with the effect that independent repair is not financially sensible: by the time you buy the new version gears, spiders, sleeves, synchros, it's cheaper to buy a reman from Porsche. There's a TSB on this. If all you need to service is for example damage to 4th, 5th, or 6th, the repair can be done economically. If OTOH you have one with the supersessions in it, the only big hassle is replacement parts cost, which is significant. Porsche slapped a "997" part number on everything in the transmission, making it inobvious where legacy parts can be used. Porsche also wants you to use a > $8K measurement bench to select the ideal tolerance needle bearing when replacing a gear, for example due to worn engagement teeth. I've improvised my way around the need for the bench by measuring with my own jig. But ya gotta wonder why we suddenly need to account for tolerance with these parts, it's a puzzle. I will probably service the G97.01 transmissions some day, but it's not today. The G97 Turbo / GT2 / GT3 transmissions are G50 based and more readily serviced.

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Yes, this is the case. 1st, 2nd, and reverse are at the top of the stack. Servicing them does not take a ton of time and does not require pressing interference-fit gears from the pinion shaft: these ones are splined to the shaft. One gotcha is the 1st/2nd shift assembly (spider plus shift sleeve): you are very likely to "sproing" the 5 mm. ball detents out of it when taking it off and putting it back on. They go flying, and they love to do that. Getting the assembly back together requires some cleverness and patience. Yes, there were some improvements that made the .2 versions more robust. One was the addition of an extra drawn-cup needle bearing supporting the input shaft. The other was the upgrade of the open differential from a two-spider-gear design to four spiders. The two-spider version breaks fairly often, and I would recommend the upgrade any time you have the chance to do so. Good used ones can be difficult to source, but they do show up on eBay, etc. from time to time. Cheers,

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Don't know. I sent my G50 to CMS. I will ask him next week. If I remember; copious amounts of beer are common when we visit.

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Based on everyone I've spoken to, the average is $4500 for a second gear rebuild. If you want to go full overhaul, then you're bumping up against $10k. But cost no object, the difference is your car gets laid up for a month versus three months.

Or consider 997 6-Speed. $3500 used? I may do that at some point. They don't suffer second gear pop out or pinion issues like the 996, are stronger, and you get slightly better gearing.

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and it fits a 996.2 C2?

Yes, 997.1 bolt configuration is the same. Later 997.2 was changed.

Does the 997 tranny match the .1 as well or only the .2?

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Interesting. Love to hear more.

997.2 uses a different engine, so bolt pattern is different. I think the 997.1 trans has the shift levers on the passenger side of the trans. The same shift cables can be used as the Turbo/GT trans has shift levers on that side too.

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Yes, that's my understanding. 997.1 transmission bolt pattern is what you would need to mate to m96 996 engines. 997.2 engine is different and bolt configuration is not compatible. GT2, GT3 and turbo won't work either. They are mezger config.