As Porsche evolved from the 996 to the 997, they incorporated the lessons they learned along the way. Among the many revisions were a heavily revised manual gearbox and the all-new PDK dual-clutch that set the motoring world ablaze with its radically quick shifts. How did each of them live up to Porsche standards, and which is the best for you? Everything you want to know and more about the Porsche 997 transmissions is right here.
Porsche 997 Manual Transmission Information/Design/Tech Specs (Aisin G97)
Porsche began using Getrag as their transmission supplier in the late eighties. That partnership remained exclusive through the 996 until Porsche decided to bring in Aisin to build the manual transmissions for the 997 Carreras. The Aisin gearboxes the outgoing Getrags, but the general six-speed manual recipe was retained. Overall ratios became shorter, thanks to the larger wheels and tires of the 997, giving them a slightly more sporty feel. As with the preceding Getrag units, the Aisin gearboxes can hold more power than stock, especially with specific supporting changes.
Aisin G97.01/G96.31 (997.1 Carrera, S, 4, 4S)
The Carreras all use essentially the same transmission. They are fully synchronized six-speed transaxles that use counterweighted cable shifters and a single plate clutch. The rear-wheel-drive models received the G97.01, while the all-wheel-drive models featured the G97.31. First and second gear use triple-cone carbon-coated synchros. The third gear uses a double-cone carbon-coated synchro, and fourth through sixth use single-cone molybdenum-coated synchros.
The all-wheel-drive models use a viscous coupling mounted to the tail end of the gearbox to send drive to the front wheels. A plate-type limited-slip differential was available for all models with this gearbox.
- Oil capacity: 2.9L API classification GL4.5 75/90 Mobilube PTX
- Clutch System: Hydraulically-assisted push-style pressure plate, 240mm unsprung clutch disc, dual-mass flywheel
- Gear Ratios:
- 1st Gear: 3.91
- 2nd Gear: 2.32
- 3rd Gear: 1.61
- 4th Gear: 1.28
- 5th Gear: 1.08
- 6th Gear: 0.88
- Final Drive: 3.44
Aisin G97.05/G96.35 (997.2 Carrera, S, 4, 4S, GTS)
The updated G97.05 and G97.35 fitted to the 997.2 are nearly identical to their predecessors. The most considerable difference for the newer gearboxes is the revised bell housing to fit the new MA1 series engines. The G97.35 gearboxes also had their viscous coupling center differentials removed for an electronically-controlled center differential. Plate-type limited-slip differentials were optional on the rear-drive models and standard on the all-wheel-drive models.
The electronically controlled center differential uses six clutches activated by electromagnets to move the torque fore and aft. The system works with PTM or Porsche Traction Management. It is controlled by onboard computers that use other sensors like steering angle, pitch, yaw, and roll to determine how much drive each axle gets for the best grip. It was developed from the PSK, or Porsche Steuer-Kupplung, first introduced in the 959 before appearing again in the 996 and 997 Turbos. All Carrera 4, Targa 4, Carrera 4S, and Targa 4S models use this system, along with PTM.
- Oil capacity: 2.9L API classification GL4.5 75/90 Mobilube PTX
- Clutch System: Hydraulically-assisted push-style pressure plate, 240mm unsprung clutch disc, dual-mass flywheel
- Gear Ratios:
- 1st Gear: 3.91
- 2nd Gear: 2.32
- 3rd Gear: 1.61
- 4th Gear: 1.28
- 5th Gear: 1.08
- 6th Gear: 0.88
- Final Drive: 3.44
Porsche 997 Manual Transmission Information/Design/Tech Specs (Getrag G97)
Porsche retained Getrag as their gearbox manufacturer for the Turbo and GT models. The 997’s Getrag box looks similar to the 996’s, but most of the internal components aren’t interchangeable. An enlarged ring gear and triple-cone synchros on every gear were new additions designed to cope with the ever-increasing power figures. Gear sets and shift forks stayed relatively the same but managed better reliability than predecessors.
For the first time, the front differential on the AWD models differed between trims. 4 and 4S variants received a smaller unit, and the Turbo, a larger one, though both are essentially the same design. Differentials aren’t a common failure, but they do occur when servicing has been ignored.
Getrag G97.50/G97.55 (997 Turbo)
The Getrag transmissions fitted to the 997.1 and 997.2 Turbo were the last manual transmissions offered by Porsche in a Turbo model. Both .1 and .2 examples use the same gear ratios with carbon-coated synchros. First and second gear are triple-cone steel synchros, while the third through sixth are double-cone. Both gearboxes also take advantage of Porsche’s electronically controlled center differential and PTM. A plate-type limited-slip differential was available optionally.
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Internal gearbox components like main shafts and gears are interchangeable with parts from the various GT models. The gearbox cases are different, though. The MA1 engine in the .2 Turbo uses a different bell housing pattern than the .1’s Mezger-based M97.
Porsche didn’t learn with the clutch system for the Turbos, though. The 997 retains the power-steering-assisted clutch designed to be softer and more usable in traffic. It was a complicated system prone to failure that delivered poor feedback through the pedal, but Porsche kept it around for whatever reason. Twenty years after its introduction, multiple companies offer a solution.
- Oil capacity: 2.9L API classification GL5 75/90 Delvac
- Clutch System: Hydraulically-assisted push-style pressure plate, 240mm unsprung clutch disc, dual-mass flywheel
- Gear Ratios:
- 1st Gear: 3.82
- 2nd Gear: 2.15
- 3rd Gear: 1.48
- 4th Gear: 1.18
- 5th Gear: 0.97
- 6th Gear: 0.79
- Final Drive: 3.44
Getrag G97.88 (997 GT2 & GT2RS)
The GT2 uses the G97.88 gearbox. It's a fully synchronized six-speed transaxle with counterweighted cable shifters and a single plate clutch. Inside, it uses a taller gear set than the Turbo but shares its steel synchros. Clutch operation is assisted by a traditional slave cylinder, differentiating from the Turbo's failure-prone power-assisted unit.
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Along with passive cooling through direct airflow over the finned exterior of the transmission case, the GT gearboxes use an attached heat exchanger. Inside the transmission is an oil pump that scavenges the oil from the differential housing and pumps it into the oil-to-coolant heat exchanger. When the internal transmission temperature sensor hits 105 degrees Celsius, the DME opens a valve, allowing the engine coolant to circulate through the heat exchanger. The valve then shuts once the temp sensor reads 95 degrees Celsius.
- Oil capacity: 2.9L API classification GL5 75/90 Delvac
- Clutch System: Hydraulically-assisted push-style pressure plate, 240mm unsprung clutch disc, dual-mass flywheel
- Gear Ratios:
- 1st Gear: 3.15
- 2nd Gear: 1.89
- 3rd Gear: 1.40
- 4th Gear: 1.09
- 5th Gear: 0.89
- 6th Gear: 0.73
- Final Drive: 3.44
Getrag G97.90 (997.1 GT3 & GT3RS, & 997.2 GT3)
The GT3 transmission is identical to the GT2 but with shorter ratios to take advantage of the screaming, naturally aspirated engine. It uses the same oil cooling system, LSD, and case.
- Oil capacity: 2.9L API classification GL5 75/90 Delvac
- Clutch System: Hydraulically-assisted push-style pressure plate, 240mm unsprung clutch disc, dual-mass flywheel
- Gear Ratios:
- 1st Gear: 3.82
- 2nd Gear: 2.26
- 3rd Gear: 1.64
- 4th Gear: 1.29
- 5th Gear: 0.94
- 6th Gear: 0.92
- Final Drive: 3.44
Getrag G97.92 (997.2 GT3RS & GT3RS 4.0)
The last of the 997 GT3RS models use the G97.92. It is identical to the gearbox used in the other GT3s but with a taller sixth gear and a shorter ring and pinion. The shorter R&P improves the acceleration but removes overall speed from the gearing. Porsche installed the taller sixth gear to get around that, restoring that top-end speed figure.
- Oil capacity: 2.9L API classification GL5 75/90 Delvac
- Clutch System: Hydraulically-assisted push-style pressure plate, 240mm unsprung clutch disc, dual-mass flywheel
- Gear Ratios:
- 1st Gear: 3.82
- 2nd Gear: 2.26
- 3rd Gear: 1.64
- 4th Gear: 1.29
- 5th Gear: 0.94
- 6th Gear: 0.88
- Final Drive: 3.88
Porsche 997 Carrera Manual Transmission Common Problems
There aren’t many issues with the G97.01 and G96.05 boxes. The Aisin gearboxes fixed the second gear pop-outs and pinion-bearing failure of the older Getrag G96 boxes. However, there are several possible fault points inside the Aisin G97s.
First Gear Jamming
An inability to enter first gear isn’t uncommon for 997 owners. The problem described by many is a reluctance to shift into first gear from a stop. The transmission either puts up a fight or refuses to engage at all because of a partially worn synchronizer. Unfortunately, there haven’t been any guaranteed cures for the problem.
Owners typically drive around the issue, finding ways to get first gear to engage naturally. Some drivers select second gear before entering first to align the synchros better, while others reselect the neutral position and re-let out the clutch to realign the synchros. Either act helps but doesn’t solve the issue. The only change that helps in any way is a switch to Mobil’s Mobilube PTX. The gear oil was designed for Porsche specifically, so it carries the characteristics that Porsche was looking for. Typically, dealerships carry Mobil 1 Delvac, the lube used for the Turbo and GT cars, and will use that to fill all manual transmissions. However, the Getrag boxes use different components inside their gearboxes and require other properties from their fluid. The PTX is simply a better fit for the Carrera’s Aisin-built gearboxes. Owners claim a near-perfect fix with the PTX, though results may vary.
First-Thrid Gear Synchro Wear
The carbon synchros in the Carrera gearboxes aren’t the strongest in the world. With a bit of track time and hard driving, owners can find themselves with some grinding and hard shifting. Unfortunately, there isn’t a quick or cheap fix. Replacing synchros requires a complete disassembly, and their superseded part numbers have kept them rather costly to buy.
Shift Fork Pads
The Carrera shift forks use two small nylon pads as the contact points with the shift sleeves. The pads are a known wear item and will eventually break off into the gear assembly. Aftermarket forks with aluminum pads eliminate any potential failure and reduce future service costs.
Broken 1st or Reverse Gear Teeth (‘05-’07 Only)
Pre-2008 manual transmissions had first or reverse gear failures due to a poorly designed mainshaft. Updating the mainshaft is doable but requires the also updated 1st/2nd gear set, 1st/2nd shift sleeve and hub, and 1st/2nd synchros.
Porsche 997 Turbo & GT Manual Transmission Common Problems
The Turbo and GT gearboxes are a completely different design to the Carrera's and use a unique internal structure. Their parts and problems are limited to the models they come in and differ from other 997s. These problems are also only an issue for heavily tracked and abused transmissions. Street-driven, unmodified cars are largely resigned from breakage.
Clutch Slave Cylinder Accumulator
The power-steering-assisted slave cylinder uses hydraulic pressure from the power-steering system to aid the slave cylinder in disengaging the clutch. It was devised to lighten the clutch pedal in the Turbo models, whose pressure plates needed to be tough to hold the engine's torque. Unfortunately, all it did was give the Turbo a vague and mushy pedal. Making matters worse, the pressure accumulator connected to the slave cylinder has a penchant for failing.
If your accumulator fails, the pedal will become much tougher to depress. Replacing the accumulator and refilling the system with fluid will remedy the failure but will leave you exposed to potential failures going forward. The other option is to delete the power-assist system and run something else. The original modification was a machined bell housing to fit the GT2's traditional slave and clutch fork. However, now there are aftermarket slave cylinders from companies like Tarret Engineering and BBi Autosport that will work with the existing bell housing pattern and clutch fork.
Oil Pump Wear
The GT2 and GT3 gearboxes are unique to all others in the 996 range as they have an internal oiling system to help keep all their moving parts happy and cool on a race track. The main component of that system is the pump, whose responsibility is to pick up and distribute the oil. Through various ways, debris can be released into the oil only to be distributed around the inside transmission. While small bits of debris from worn oil aren’t an enormous deal, metallic bits from rushed synchros and worn bearings are.
In many cases, the contaminated oil is then picked up and distributed through the oil pump. Unfortunately for owners, that debris can and will wreck the inside of the oil pump and necessitate a replacement. It’s around $2000 for a new pump. Porsche did place a screen on the oil pick-up, but those are ineffective. The best solution is to have the oil filter from a Cup Car (race car) gearbox fitted along with regular oil changes after track days.
Synchros/Shift Sleeves/Gears
Issues on all of the Mezger gearboxes are worn synchros and shift sleeves. Looking around the forums, you’ll find countless threads on second-gear problems, and in just about every case, it is user generated error. Lack of rev matching or poor efforts combined with the hard shifting conditions of a drag strip, autocross, or track day will wreak havoc on them. First to go are the engagement teeth before stresses get to the shift sleeve and then eventually the gear itself. While most common on second gear, it isn’t out of the ordinary to see them on third and first as well. The synchros in the GT and Turbo boxes use steel synchros on gears 3-5, so they’ll tend to take the abuse better. Replacing 2nd gear with new synchros and a 1-2 shift sleeve is another repair that is nearly $2000 in parts.
In modified applications, the gears themselves can also break. All street Mezger gearboxes run cast gears from the factory, and although they can take a good amount of power, they aren’t indestructible. It isn’t always the power that gets to them, though. Wide and sticky tires can put additional stress on the transmission housing, which is then transferred internally to the output shaft and the gears themselves. A forged Porsche Motorsport Cup Car or aftermarket gearset are the standard replacements for weaker factory pieces.
Case Bearings
While stress from stickier tires can assist with breaking gears, owners will generally see those forces affecting output and input shaft bearings. Again, this is an issue on neglected and heavily tracked transaxles. The stresses put through the case, especially the output shaft, can tax the bearings to the point that they will degrade fairly significantly if not serviced properly.
The worn bearings will create a whirring or almost gravel-like noise while the clutch is engaged. On top of the importance of having healthy bearings, you need to watch out for the debris they cause when they wear beyond acceptable levels. In most cases, the rollers force themselves against the races, pitting the race surface into something that mirrors the moon's surface. The metallic debris sent through the gearbox will then damage the rest of the bearings and the internal oil pump (GT only).
Tensioning Plate
The tensioning plate, also called the bearing retainer plate, is responsible for holding the main input and out shaft bearing inside the gearbox. Under normal driving conditions, the bearing plate is already a wear item, but more horsepower and extensive track time do increase the wear rate. If left for too long, the bearings will spin inside the plate, effectively killing it. If there’s an upside to this issue, it’s that it’s uncommon to happen before other bearing issues and should only require replacement with other gearbox servicing.
Shift Fork Roll Pin
The first and second-gear shift fork is secured to its rail via two roll pins. It isn’t unusual for the pins to begin to walk in the bores and back themselves out after abuse. The pins aren’t small and will get caught in the gears if they back out. The fix here is a new fork and some safety wire through the roll pins, just like Porsche used in their Cup Car gearboxes.
Clutch Fork Pivot Shaft Boss
The clutch fork rides on a shaft that sits in two bosses cast into the transmission case. Cast aluminum is strong, but heavier clutches and hard use will wear them down. Cracked bosses will affect clutch operation and can put lateral loading on the throw-out bearing, which will cause abnormal guide tube wear.
There are a few fixes here with varying levels of intensity. The “easiest” repair is to grind and weld the cracked bosses. However, cracks can form along the welds or on other places of the boss, so it isn’t a guaranteed lifetime fix. The other way is to lop the outer half of the boss off, drill and tap some bolt holes, and use an aftermarket cap to form the boss from a stronger material.
Porsche 997 Manual Transmission Service Intervals
Just like engine oil, transmission oil needs replacement. Transmission efficiency and reliability shrink when fluid becomes worn, causing the synchronizers to wear excessively. Porsche recommends a fluid change every 120,000 miles or 12 years to stem that wear, whichever comes first. However, many independent shops, especially those specializing in rebuilding these Porsche transmissions, recommend more frequent servicing. Replacing the fluid after 50,000-80,000 miles will ensure the transmission has suitable fluid throughout operation.
The fluid used in replacement also plays a crucial role in longevity and servicing requirements. The Turbo and GT models use Mobil 1’s Delvac fluid in a 75-90W specification. It meets the GL5 specification, which is suitable for severe service and shock loads, seemingly a good thing for transmissions. However, it contains sulfur and phosphorus additives which can wear out synchronizers that utilize copper and bronze, like those found in the Aisin gearboxes. To remedy that, the 997 uses Mobilube PTX, which has all of the best GL5 properties without the synchro-killing additives. Always use PTX in a Carrera box to avoid premature wear. Turbo and GT boxes with their steel synchros should continue to use the Delvac.
Porsche 997 Manual Transmission Modifications & Upgrades
The Aisin gearboxes benefit from the upgrades that helped the older Getrag G96s. Mostly feel-related items, they’re inexpensive to acquire and add a bit of personal flair to the car. The Getrag boxes used in the GT and Turbo models are infinitely more adaptable. Complete gear sets and final drive changes are regular changes made by those looking for more track-day performance. From mild to wild, there is plenty to do.
Short Shifters
By far, the most common upgrade to the drivetrain is some sort of short shifter or shift upgrade kit. Plastic deteriorates over time, and the OE Carrera shifter assemblies are full of them, making shifting less than enjoyable. There are plenty of options when it comes to upgrading here, from the standard 997 short shift kit, to the 997 GT3RS shifter, to Numeric Racing’s CNC aluminum shift assembly. You can keep your stock housing and replace the internals with the EVOMS billet short-shift kit or the Ben Auto Design piece.
Ensure you understand all of the risks before installing any aftermarket parts. Porsche designed their shifter assembly with the synchro tolerances in mind. Aftermarket pieces shorten the synchros’ time to engage the next gear, putting extra strain on the synchros. The OEM short shifter assembly isn’t a fix either, as its transmission uses different synchros. You’ll be hard-pressed to find owners who share the same thoughts, though, so install at your own risk.
Shifter Bushings
Fixing a sloppy shifter doesn't have to come from a new shift assembly. Phenix Engineering and Function First offer solutions that work with the factory shifter assembly for those who like a DIY project. Although they aren’t exactly the same, both kits replace the original plastic bushings with machined aluminum pieces.
Limited-Slip Differential
Aisin provided an optional clutch-type limited-slip differential for every Carrera model, while Getrag offered their own version for their gearboxes. However, both options are very uncommon, so an aftermarket differential is the easiest way to cure an open differential. Several aftermarket companies like Guard Transmission, Quaife, and Wavetrac offer differentials for the Carrera and the Turbo transmission in true clutch-type LSD and torque biasing form.
Ring & Pinion, & Gear Set Changes
Porsche designed their gearboxes with fuel economy and everyday road situations in mind. Because of that, the ratios are relatively tall, meaning that the transmission is geared for top speed rather than acceleration. That gearing choice takes away from the performance of the 997 on most race tracks, where short bursts of acceleration are needed between corners. Thanks to companies like Albins and Guard Transmission, any 997 GT model or manual-equipped Turbo owner can alter their gearing.
Albins offers a change of ring and pinion, also known as the axle ratio or final drive. On all Getrag boxes but the 997.2 RS, the final drive is 3.44, meaning that the engine makes 3.44 rotations for one full wheel rotation. Albins offers the 997 Cup Car ring and pinion, which sits at 4.00. That shorter ratio essentially shortens the entire gear set, reducing the top speed and increasing the acceleration in each gear. On the other hand, Guard Transmission offers a slew of individual gears for anyone interested in building their perfectly specced gearbox. Both of these modifications aren’t for the faint of heart, nor are they for the faint of wallet. However, there really isn’t anything better to do for the drivetrain than build it better for the racetrack.
Porsche 997 Tiptronic S Transmission Information/Design/Tech Specs
The Tiptronic S transmission is a five-speed automatic transmission that is essentially a Mercedes-Benz 5G-Tronic 722.6. Porsche bought them from Daimler, Mercedes’ parent company, gave it the internal designation of A97, and made it an option in all non-GT 997.1 models. They use a traditional torque converter and valve body supported by an adaptive computer that programs its shifts based on the driver and “Sport” and “Normal” modes. The Tip also has a manual mode, where the driver can select the upshifts and downshifts themselves. Overall, they work well, are cheap to replace, and can take a beating if desired.
The Sport Chrono package was made available with the 997’s introduction and added the “Sport” button to the interior. Setting the car into “Sport” activated a unique transmission shift map, increasing the engine speed for shift points and quickening the shifts. Selecting manual mode while in Sport allowed the driver to take complete control of the shifting, with the TCU shutting off automatic upshifts even when bouncing off the limiter. It provided the fastest shifts of any automatic fitted to a 911 to that point. Also helping to quicken shifts was a lighter-weight oil and modified shifting plates for less resistance.
Like the Getrag boxes fitted to the GT cars, the A97 also benefited from an attached coolant-to-ATF heat exchanger. Automatic transmissions naturally get hot quickly, so the attached heat exchanger ensures a proper operating temperature. Much of the heat in the fluid comes from the torque converter. For the A97, Porsche modified the engagement curve of the lock-up, allowing for smoother shifts in relaxed driving and quicker ones during intense running.
- Gear Ratios:
- 3.56 (A97.01/.31)
- 3.06 (A97.50)
- 1st Gear: 3.60
- 2nd Gear: 2.19
- 3rd Gear: 1.41
- 4th Gear: 1.00
- 5th Gear: 0.83
- Final Drive:
Porsche 997 Tiptronic S Transmission Common Problems
There isn’t too much to write about with the Tiptronic S. It was well-developed when Porsche began using it and remained a reliable performer. The most common issues with the Tips are fluid leaks. Any Porsche dealership will typically want to replace the transmission as a whole unit, even for just a leak. Instead, head to an independent Mercedes repair specialist. They are far more adept at repairing and servicing the 5G-Tronic gearboxes. Replacement repair parts are widely available and easily accessible. Used Tips are also a dime a dozen if needed for a complete replacement.
Porsche 997 Tiptronic S Transmission Service Intervals
Servicing a Tiptronic S transmission is easier said than done. The fluid replacement process requires a pan and filter replacement before filling the transmission with fluid. Once filled with fluid, it must be heated to operating temperature and then have its level checked and adjusted. The tools needed to perform the procedure aren’t typically found in every garage, so it’s best to let a professional handle the service. Porsche states service must occur every 120,000 miles or 12 years, whichever comes first.
Porsche 997 Tiptronic S Transmission Modifications & Upgrades
The Mercedes-built Tiptronic S was a common choice among several manufacturers. As such, its aftermarket development was decent, leading to several aftermarket options for improving its reliability and power-handling capabilities. However, the upgrades are primarily for the 997 Turbo.
Torque Converter
Upgraded torque converters for the Mercedes 722.6 are available through several companies. However, few list the 997 as compatible, so the most available options are the unit provided by Evolution Motorsports and the piece by RENNtech. They feature new vanes inside the converter for a higher stall speed and hold 800hp reliably. That power level isn’t crazy for the 997, but more than that will require more from the transmission.
Software Flash
Quicker cars need quicker shifts; that’s how it goes. Evolution Motorsports offers a software flash for the transmission control unit to go along with their torque converter. Porsche’s TCU controls the shift points, speed, and torque limit at certain RPMs. EVO’s software raises those shift limits, increases the available Torque, and quickens the shifts to take advantage of the extra power. Other companies also offer TCU flashes for the 997, including GIAC and MarkSKi Tuning.
Complete Build Packages
If your 997 Turbo will put down over 1000hp, the best upgrade path is a full-build package capable of such power. That leaves the Tiptronic in the hands of RENNtech. They offer a complete package with upgraded clutches and other internal components to withstand the constant abuse of four-figure power.
Porsche 997 PDK Transmission Information/Design/Tech Specs
The Tiptronic S transmission did a fine job while in service, but its performance wasn’t enough for Porsche. They needed a non-manual transmission option for the 997.2, but it had to be better. Cue the Porsche Doppelkupplung Getribe, better known as the PDK. Porsche had been developing the PDK since the mid-eighties, and it finally became a viable option with advancements in computers, sensors, and solenoids. It wasn’t the first transmission of its kind, with the GTI using one starting a few years earlier; however, it was immediately recognized as one of the best around.
Porsche’s PDK transmission is a dual-clutch transmission with seven forward gears. Built by ZF, it uses separate clutches for each of the rotating gear shafts that allow each shaft to pre-select the next gear so that shifts happen in a hundredth of a second. Those shifts are snapped off by a hydraulic system that operates the two clutch packs. It is significantly more advanced than the Tiptronic, although it has the same function. When shifted into drive, the PDK acts like a standard automatic transmission with tighter shifts. Slip it into manual mode, and the driver controls the up and downshifts. Launch control was also added with the PDK, allowing the Turbo models to become the benchmark 0-60 times.
The PDK was available in all non-GT 997.2s and was the only option on the Turbo S. They were available in the rear and all-wheel-drive models. The Sport Chrono Plus option added the launch control and the “Sport Plus” setting in the car. Pressing the Sport+ button sharpens the PDK’s shifts and causes it to hold gears longer. It also added a light-up bar at the top of the steering wheel that indicated when Sport Plus and launch control were activated.
Over ten years since its debut, the PDK has proven to be relatively bulletproof. The earliest cars from 2009 did have some teething issues, but the number of overall PDK failures is low. Porsche doesn’t repair broken PDKs and chooses to replace them, no matter the fault, so you’re in for a costly repair if one does go. Luckily there are plenty of healthy used PDKs floating around at dismantlers.
CG1.00/CG1.30 - 997.2 Carreras
- Gear Oil: 2.9L API classification GL4.5 75/90 Mobilube PTX
- Hydraulic Oil: 5.5L Pentosin FFL3
- Gear Ratios:
- 1st Gear: 3.91
- 2nd Gear: 2.29
- 3rd Gear: 1.65
- 4th Gear: 1.30
- 5th Gear: 1.08
- 6th Gear: 0.88
- 7th Gear: 0.62
- Final Drive: 3.44
CG1.50 - 997.2 Turbo & Turbo S
- Gear Ratios:
- 1st Gear: 3.91
- 2nd Gear: 2.29
- 3rd Gear: 1.58
- 4th Gear: 1.18
- 5th Gear: 0.94
- 6th Gear: 0.79
- 7th Gear: 0.62
- Final Drive: 3.44
Porsche 997 PDK Transmission Common Problems
The idea for a dual-clutch transmission had been floating around Porsche since the 1960s. When it made its way into a production car, the PDK had gone under incredible amounts of engineering and development. From that, the PDK has gained a reputation for being relatively reliable, as the failure rates are minimal. Owners have found most hard-shifting issues or things of that nature have been solved by software updates, fluid changes, and clutch recalibrations. Under stock power, they’ll hold up to hundreds of repeated launches with launch control without breaking or overheating. They perform just as well with track days and intense, spirited driving.
However, none of that means they’re perfect. The PDKs occasionally come down with shifting or sensor issues or leaks. According to Porsche, they are entirely sealed units that cannot be repaired. Meaning that anything a dealer cannot fix will require a complete transmission replacement. New gearboxes cost well over the $20,000 mark. Independent PDK repair specialists and a few dealerships in the US are licensed to repair them, making that a potentially less expensive option. However, most owners opt for a used replacement instead.
Porsche 997 PDK Transmission Service Intervals
Porsche specifies a PDK fluid and filter change every 60,000 miles. The PDKs work hard, and the 60,000-mile service interval ensures they have quality oil for operation between changes. Like Tiptronic, the service isn’t manageable in a driveway. Porsche’s PIWIS diagnostic computer must set the PDK into “Fill Mode” and read the fluid temperature to add it in at the right time. The PDK then needs to be shifted through all gears while stationary on a lift to ensure the fluid has reached everywhere it’s needed.
Porsche 997 PDK Transmission Modifications & Upgrades
The PDK is a reasonably stout transmission out of the box. However, Porsche Turbos of any generation are known for producing and handling enormous power numbers thanks to their engineering. Once the cars get to half-mile and full-mile roll race power, the PDKs begin to struggle. It has taken a few years since their initial offering, but the aftermarket has caught up and now offers a few pieces to keep the PDK happy.
TCU Flash
How Porsche allows the PDK to perform is based on safety and longevity. Typically, the TCU softens its engagement and torque limits to ensure the clutches last for life, but that doesn’t really work for upgraded engines. The easiest way to remedy light clutch slipping or engine cut-offs from exceeding a torque limit is to reflash the transmission control unit. The transmission control unit keeps the transmission running and shifting as it should according to the parameters it uses. However, you can flash or remap them to alter those parameters for better performance. FVD Brombacher offers a few stages of flash for the TCU that increases the maximum clutch pressures to improve the torque capability and the response time of the shifts.
Owners can also reflash their PDK using COBB’s Accessport. The PDK tuning comes as an extra with one of their Accessport Tuners—piggyback tuners that offer transmission and engine software modification. The Accessport works best when engine and PDK tuning are needed together and provides a reasonable package price. However, the FVD tune is less expensive and is strictly for the TCU, potentially making it a better option for pre-tuned engines.
Clutch Replacement
The torque limit for the RWD PDK clutches comes at about 600 wheel torque. The all-wheel-drive units fitted to the Turbo and Turbo S are considerably stronger but wear quicker under higher power loads and will begin to slip within the power potential of the Turbo engines. Porsche doesn’t offer any stronger components, but the aftermarket does.
Dodson Motorsports has the largest availability of PDK upgrade components. Among their parts are four different clutch kits designed to increase the torque capability of the PDK. They feature parts made from steel billets and hand-made clutch discs in a complete package for the 997.2 and 991 PDKs. A single kit with eight clutch discs is offered for the rear-wheel-drive models, while the all-wheel-drive models have a choice of a seven, eight, or ten-disc kit. All kits make the clutch assembly serviceable and ready for future upgrades. However, the ten-disc kit is the top of the line and has held over 1000 lb-ft of torque on the dyno.
There is another option, too. German company speedART also offers a PDK upgrade package. Dodson doesn’t list any pricing on their website, but speedART lets you know about the nearly $12,000 cost upfront. That’ll get the PDK a very similar treatment to the Dodson kits; extra upgraded clutches for reduced thermal loading and increased torque capabilities. The only negative to the speedART package is the necessity of shipping the transmission to Germany to have them perform the upgrades.
Billet Oil Pan
Regular abuse stresses the transmission case, and although it doesn’t cause catastrophic failures, it does wear on the components inside and around it. Like torsional stress, heat also greatly affects a transmission's longevity. The plastic oil pan used on the PDK works well in stock applications but is a source of weakness for the case as it covers a large hole with no additional torsional support, and it must be replaced during every service. Several companies have come up with solutions to get around that.
Bilt Racing Services and Dodson Motorsports offer pans made from aluminum billets with their own individual upgrades. The less expensive BRS pan, offered through LN Engineering, features a finned design to add some cooling efficiency and room for an additional half-quart of fluid. The Dodson piece carries the original amount of fluid but features a similar finned design for cooling. That piece also offers additional bracketing for the differential side plates to help with the increased torsional load of upgraded engines. Both pans use a replaceable filter, negating the need to replace the pan during every service. Either pan is a good choice for a PDK car seeing extensive track time.
There’s a lot going on with all of the 997’s transmission options. Eight years and three distinct transmission options make for a dense read. However, this should be everything needed to help inform you, a prospective purchaser, on what you need to know. As always, follow along on our blog and subscribe to our YouTube channel for more great DIY and entertainment content.
