In this article, you will learn about some of the most common problems that affect Porsche automatic transmissions.
Limp-home mode
Older Porsches with a 5-speed Tiptronic transmission can have an intermittent issue that will manifest itself as delayed and harsh gear changes in initial phases. This problem tends to get worse with time, ending up with transmission going into a limp-home mode. Usually, the problem will be more noticeable when the vehicle warms up. In most cases, this will check engine light, so there will be a corresponding error code stored.
Possible causes and solutions:
- Cracked or damaged conductor plate that serves as a carrier and linkage between solenoids and the TCU. Any faults within this plate will result in communication problems, which will cause improper solenoid operation. This is a well-known problem, and there are numerous aftermarket solutions.
No 5th gear in automatic mode
Many older Porsches that come with a 5-speed Tiptronic transmission can develop a very specific symptom that may seem very intermittent. The transmission may seem to work flawlessly but will not upshift to 5th gear in automatic mode. When in manual mode, it will perform this gear change without any apparent problems. There will be no other symptoms or transmission-related warning.
Possible causes and solutions:
- Underinflated tire or tires, which sets the transmission into a mode where it doesn’t shift into 5th gear. This is a safety feature that is meant to remind the driver to check the tire pressure and has nothing to do with the transmission itself. Setting the tire pressure to a correct level solves the issue.
Shift flares
Some Porsches that use a 5-speed Tiptronic transmission can suffer from shift flares that can occur both on acceleration or while downshifting under load. While most vehicles only exhibit mild symptoms, it is possible for flares to become too severe and send the transmission into limp-home mode. The problem is usually intermittent and comes without any other symptoms.
Possible causes and solutions:
- Worn bores inside the valve body, which causes leakage and sporadic pressure loss. As this type of transmission relies on correct transmission fluid pressure, this will cause delays and flares when shifting. This is a known issue, and there are several upgraded aftermarket kits that can solve it.
Harsh and delayed gearshifts
Porsche Cayennes with a 6-speed automatic gearbox, designated as TR-60SN, can suffer from harsh upshifts during acceleration or delayed downshifts that appear only when coming to a stop. In initial phases, this issue will manifest itself only while the vehicle is cold and on mild accelerations but gets worse with time. In most cases, there will be no other symptoms.
Possible causes and solutions:
- Worn bores inside the valve body, with a solenoid modulator valve or clutch control valve being the most commonly affected. Instead of replacing the valve body, it is better to install upgraded valve kits for these locations, which are available as aftermarket parts.
Difficult or impossible gear engagement
Porsche Boxsters and Caymans with a 6-speed manual transmission can have issues when selecting certain gears. This can manifest itself as a difficult gear engagement, with the driver having to repeat the procedure several times until it succeeds. In worse cases, the transmission will remain stuck in one gear and will not react to driver inputs.
Possible causes and solutions
- Worn bushings under the shift lever, causing a misalignment that results in difficult gear changes. In most cases, this affects reverse gear more than forward ones. Renewing the bushings and performing a cable adjustment afterward solves the issue.
- Broken or disconnected shifter cables, which causes an instant loss of ability to shift gears. The car will remain in gear it was in before this happened while the shift lever moves freely around.
Many newer Porsche cars and SUVs use the 7-speed PDK transmission, which comes with its own set of problems. However, based on our experience and research, there are limited repair experts for PDK transmission. Also, Porsche doesn’t sell any spare parts for this transmission, nor do they allow their dealerships to repair them in any way. Therefore the majority of problems in this list affect Porsche vehicles with Tiptronic transmission.
If you are a Porsche owner experiencing problems with the automatic transmission, we strongly recommend checking the transmission fluid level first. Low transmission fluid is a common problem with Porsche transmission, which causes a number of symptoms, including transmission slipping, hard shifting, limp mode, transmission not going in gear, etc.
If the transmission fluid is not the issue, read the fault codes from the transmission control unit (TCU) with a Porsche scanner.
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