In what way is a GT3's Transmission different than a 997?
#16
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The G96/G97 gearbox in the 996/997 Carrera/S is a low cost transaxle for high production that is not designed to be serviced with assembly in Japan. The German Getrag GT3 (G96/96) is basically a full race gearbox: larger/stronger gears, beefier case, differential, ring and pinion. Being as such, a GT3 transmission runs about $15K new versus $6K for a G96/G97, Shifting mechanism is different inside the transaxle with the cables flipped from regular G96/G97. GT3 has a stiff and very direct feel. When you move the lever, you can feel some of the mass of the beefier components inside.
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#18
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My 01 Boxster S got one free transmission under warranty, it would not go in 2nd gear. My 1999 SpecBoxster broke a complete transmission at an autoX nonetheless, but it was a cheap fix, I bought an used one for $1,000 and got it installed for free by a good friend (and Boxster guru). The Cayman transmission is still the original, but the car has only been driven at 8 track days, 2 in California (Streets of Willow) 6 in Florida (Sebring and Homestead), 42k miles, with less than 700 miles on track use.
Every track day breaks something.
My 996 GT3 and 997.1 GT3 RS on the other end, had super reliable transmissions. The 996 GT3 unit was replaced under warranty due to a worn out Limited-Slip Diff (not a transmission problem), and PCNA gave me a new tranny. Both of them had problems going from 2nd to 3rd, but I never did the solid engine mounts combined with tranny mount that reduces this problem.
Every track day breaks something.
My 996 GT3 and 997.1 GT3 RS on the other end, had super reliable transmissions. The 996 GT3 unit was replaced under warranty due to a worn out Limited-Slip Diff (not a transmission problem), and PCNA gave me a new tranny. Both of them had problems going from 2nd to 3rd, but I never did the solid engine mounts combined with tranny mount that reduces this problem.
#19
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The German Getrag GT3 (G96/96) is basically a full race gearbox: larger/stronger gears, beefier case, differential, ring and pinion. Being as such, a GT3 transmission runs about $15K new versus $6K for a G96/G97, Shifting mechanism is different inside the transaxle with the cables flipped from regular G96/G97. GT3 has a stiff and very direct feel. When you move the lever, you can feel some of the mass of the beefier components inside.
#20
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#21
Race Director
#22
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The G96/G97 gearbox in the 996/997 Carrera/S is a low cost transaxle for high production that is not designed to be serviced with assembly in Japan. The German Getrag GT3 (G96/96) is basically a full race gearbox: larger/stronger gears, beefier case, differential, ring and pinion. Being as such, a GT3 transmission runs about $15K new versus $6K for a G96/G97, Shifting mechanism is different inside the transaxle with the cables flipped from regular G96/G97. GT3 has a stiff and very direct feel. When you move the lever, you can feel some of the mass of the beefier components inside.
The shortcoming of the box is the press fit gears that only allow you to rebuild it once before the tolerances get too loose and you've got to toss the shafts. But by then your ring and pinion and 1st/2nd gear should probably be timed out anyway. But service parts are readily available for them, and unlike the GT3, you can buy just a single loose 2nd gear idler gear if you have bad dog teeth. On the GT3 one must buy an all new mainshaft with 1st and 2nd attached to the tune of $2000 instead of the $350 the G96.01 2nd gear idler costs.
The G97 gearbox is the Aisin gearbox. And as of about a year ago it also became serviceable. You can buy bearings and synchros for them but they are stupid expensive. Designwise, it's pretty much a Japanese knockoff of the G96.01, though there is no parts cross compatibility. And 3rd gear does seem to be weak and a problem child on it when they are raced. But on the upside the ratios are a bit tighter together and shorter than the G96.01 ratios. And if one has an LSD equipped one, it's actually a decent functioning LSD that lasts a fair bit of time on track. GT3s don't get that.
The jury is still out on the 991 GT cars. The 991 Carreras are getting the PDK based 7MT. But here's the really weird one on this front. The PDK is a ZF designed and manufactured gearbox. The 991 7MT has been farmed out to Aisin. I'm totally amazed that ZF/Porsche would share the technology like that. Maybe the cost benefit of having them made in Japan/SE Asia makes it worthwhile. It is just out of character for them to share technology that openly and I also wonder how the bean counters at Porsche sold ZF on the idea unless they get a really nice fat licensing check for every gearbox made by Aisin.
#23
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Still, been keeping an eye out for a GT3 for a while now, no rush, trying to be patient (which is not a quality of mine)!
#24
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So both transmissions use a cable shift linkage? Are there ever additional gates actually on/in the shifter mechanism? Is play ever introduced due to cable problems?
If they use cables then why do the engine/transmission mounts cause issues with shifting? (mentioned earlier)
I understand why it does on my VW beetles, that is obvious with the tunnel linkage. I just don’t understand why it would be a problem with cables with endpoints directly on the transmission.
As far as the POS thing... I'm not going to argue that point when my engine blew and now the repair is > 1/2 the value of the car.
If they use cables then why do the engine/transmission mounts cause issues with shifting? (mentioned earlier)
I understand why it does on my VW beetles, that is obvious with the tunnel linkage. I just don’t understand why it would be a problem with cables with endpoints directly on the transmission.
As far as the POS thing... I'm not going to argue that point when my engine blew and now the repair is > 1/2 the value of the car.
#25
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Porsche 918 Spyder -- PDK Transmission...
![](http://www.excellence-mag.com/images/0000/1366/203EHybrid1_big.jpg)
According to Exce11ence, the PDK transmission in the 918 Spyder is based on the unit found in the 997 Turbo...
![](http://files.porsche.com/filestore.aspx/normal.jpg?pool=germany&type=image&id=997-2nd-tu-detail-drive-pdk-xle&lang=none&filetype=normal&version=b84d7364-b82d-4c43-ba47-ee4e2932b674)
...and a few comments on the V8 engine...
< Porsche 918 Spyder -- Exce11ence article link > ![burnout](https://rennlist.com/forums/graemlins/burnout.gif)
![](http://www.excellence-mag.com/images/0000/1366/203EHybrid1_big.jpg)
According to Exce11ence, the PDK transmission in the 918 Spyder is based on the unit found in the 997 Turbo...
![](http://files.porsche.com/filestore.aspx/normal.jpg?pool=germany&type=image&id=997-2nd-tu-detail-drive-pdk-xle&lang=none&filetype=normal&version=b84d7364-b82d-4c43-ba47-ee4e2932b674)
To lower the V8, the PDK transmission is “upside down,” 935 style. The ’box is based on the unit found in the 997 Turbo, but gets a new case and internals...
Porsche says the 918 Spyder’s 4.6-liter V8 is just 25 pounds heavier than its 3.4-liter counterpart in the LMP2-class RS Spyder race car...
...lightweight bits like the titanium connecting rods, the plastic oil-extraction pumps, and the thin-walled crankcase which, like each cylinder head, is the result of low-pressure casting. The lightweight steel crankshaft maintains the RS Spyder’s “flat-plane,” 180° crankshaft to maximize volumetric efficiency at high engine speeds, critical with an engine that makes peak power at 9000 rpm...
...lightweight bits like the titanium connecting rods, the plastic oil-extraction pumps, and the thin-walled crankcase which, like each cylinder head, is the result of low-pressure casting. The lightweight steel crankshaft maintains the RS Spyder’s “flat-plane,” 180° crankshaft to maximize volumetric efficiency at high engine speeds, critical with an engine that makes peak power at 9000 rpm...
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jaredomin (02-24-2020)
#27
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The jury is still out on the 991 GT cars. The 991 Carreras are getting the PDK based 7MT. But here's the really weird one on this front. The PDK is a ZF designed and manufactured gearbox. The 991 7MT has been farmed out to Aisin. I'm totally amazed that ZF/Porsche would share the technology like that. Maybe the cost benefit of having them made in Japan/SE Asia makes it worthwhile. It is just out of character for them to share technology that openly and I also wonder how the bean counters at Porsche sold ZF on the idea unless they get a really nice fat licensing check for every gearbox made by Aisin.
Generalising, Japanese drivers are quite abusive of gearboxes, hence their manufacturers have developed pretty tough manual transmissions and have removed some of the slush from the automatics. It seems sensible to make use of this technology. On the other hand, many Germans understand far too much about how fragile gearboxes can be and to this day handle their transmissions with a level of care and consideration not encounted in many other places. This is good for Hansel und Gretel, but not so not for those whose sporting driving is limited to accelerating away from the lights at T-junctions. Hence the interest in Japanese transmissions.
I have driven, and tested the GT3 box inverted and installed in a mid engined configuration. With one caveat, I'd say it works pretty well. The problem, which is not entirely resolved owing to a shortage of demand, is the need to ensure that there is an extra series of oil pick-ups to maintain adequate lubrication when operated in this configuration.
Ultimately, the most satisfying automated manual transmissions (flappy paddles to most of us), are those with a single clutch. Many purist engineers find the double clutch offensive in that it is inherently wasteful and heavy - would Colin Chapman have tolerated one?
R+C
#29
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A Carrera S is neither a POS (using the accepted definition) or a poseur ride. A shame that a legitimate question gets answered with that kind of BS from someone who obviously doesn't have the real answer. As I have had the same question thanks to all those who replied with information rather than insults.
#30
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so it is still does not make sense to try to repair one, it is simpler to find a used one for a complete swap, price wise?