Changing your automatic transmission fluid (ATF) and transmission filter is important to keep your drivetrain smooth. While performing this service isn’t technically hard, filling the transmission fluid to the precise level is difficult without some experience. Therefore, we do not advise you attempt to do-it-yourself unless you are comfortable working on cars.
While Porsche recommends owners change the ATF and transmission filter every 16 years or 160,000 miles, we believe this is too long. For an overview of the procedure, check out the procedure from the YouTube channel, DIY Dan. Although this video covers the 955/957 generation, the procedure is similar on the 958 Cayenne. Even if you don’t feel comfortable performing this service yourself, you can still save a bunch of money by purchasing the parts required online and paying an independent mechanic for just the labor.
Tools Required:
- Mechanic’s Tool Set
- Torx Bit Socket Set, T10-T60 (T40 Torx bit for drain plug)
- K Tool International Low Profile Jack (3.33 Ton)
- ESCO 10498 Performance Jack Stands (Pair) (4 jack stands required)
- Wheel Chocks
- 1/4 Inch Drive Click Torque Wrench (20-200 in.-lb.)
- 09G Transmission Service Oil Fluid Filling Adapter (for fill plug)
- Fluid Transfer Pump Kit
- Foxwell NT510 Elite OBD2 Diagnostic Scanner (for Porsche) (required for ensuring proper ATF level)
- Etekcity Lasergrip 774 Digital Infrared Thermometer (less accurate alternative for measuring ATF level)
- Oil Drain Pan, 16 Quarts Capacity
- Safety Glasses
- Disposable Gloves
Parts Required:
- Pentosin ATF 1LV Transmission Fluid, 5 L - P/N: 1088206, 95830054000, G055540A2 (10 liters required)
- VAICO Automatic Transmission Filter - P/N: V102284, 95832543500
- VAICO Automatic Transmission Pan Seal - P/N: V102285, 95832137100
- Genuine Porsche Auto Trans Drain Plug Seal - P/N: 95832158100
- Rubber O-Ring Assortment (HNBR) - P/N: B07RJHKZPH
Torque Specs & Fluid Capacities:
ATF Fluid Capacity: 10 liters
Oil Drain Plug: 15 ft-lbs
Fluid level insert: 1.5 ft-lbs
Transmission Filt Bolts: 7.5 ft-lbs
ATF Pan Bolts: 6 ft-lbs
Step-by-Step Instructions:
Step 1: Prepare your vehicle and work area.
- Start with a cold engine, so you can measure the ATF level correctly.
- Park your car on a flat surface.
- Gather required tools and parts.
- Put on gloves and eye protection.
Step 2: Raise your vehicle to give yourself extra clearance.
- If you have air suspension, simply raise your car to the highest ride height.
- If not, raise your vehicle with a lift or jack stands; it is very important your car is level during the procedure.
- If using a jack and jack stands, be sure to engage parking brake and use wheel chocks to prevent your car from rolling.
- To get jack stands on the front jack points, jack the vehicle by the center cross member as shown in the photos.
- To get jack stands on the rear jack points, jack the vehicle up be the rear cross member which is just ahead of the rear differential and in between the exhaust pipes.
- Once your vehicle is in the air, give it a hard shove to make sure it is securely supported.
- NEVER rely on a jack to support your vehicle.
- Note: If you have air suspension and decided to jack up the car, you will need to lock the air suspension by starting the car and holding the air suspension button up for 10 seconds. You will see an indicator pop up on your gauge cluster.
Step 3: Remove the underbody trays.
- Remove front underbody trays, which are held on by several T25 Torx screws and 10mm bolts.
- Also remove the panel covering the mid section of the vehicle, which is held on by 10mm bolts.
- Once you unclip the midsection underbody panel, use a 10mm socket to unbolt and remove the metal brackets at the end.
- Locate the transmission (towards middle of vehicle).
Step 4: Drain the transmission fluid.
- Unlike what’s shown in the video above, the 958 Cayenne transmission uses a single port to drain and fill the transmission fluid.
- The process for draining the ATF is identical to one shown in the video from Blauparts LLC.
- Place a drain pan under the drain plug, then remove the drain plug using a 5mm allen bit and ratchet.
- Next, inside the drain port, you will find a fluid level insert; remove it using a 5mm allen bit.
- Allow the transmission oil to drain until there isn’t much left coming out.
- Reinstall the drain plug and tighten it by hand; this will make removing the transmission pan less messy.
Step 5: Remove the transmission pan.
- Place cardboard or something absorbent under the transmission pan to catch any fluid that may come out.
- The transmission pan is held on with numerous 10mm bolts. Loosen but do not fully remove these bolts.
- Because of the transmission pan seal, th pan may remain stuck to the transmission.
- If necessary, use a flat head screwdriver to carefully pry the transmission pan loose.
- Then fully remove the bolts and carefully drop the transmission pan.
- Pour any remaining transmission fluid in the pan into your drain pan.
Step 6: Remove the transmission filter.
- The transmission filter is held on by four 10mm bolts.
- Remove these bolts, then pull the transmission filter out.
- Pour any fluid inside the transmission filter into your drain pan.
Step 7: Clean the transmission oil pan.
- Take paper towels and wipe down the transmission pan.
- Use an all-purpose degreaser such as dishwashing soap to thoroughly clean the transmission pan and magnets.
- Dry the transmission pan and place the magnets back int their proper positions.
Step 8: Reinstall the new transmission filter.
- Install the new o-ring gasket onto the transmission filter intake port and apply a light coating of new ATF fluid on the o-ring.
- Place the transmission filter back in the transmission and ensure the o-ring gasket is seated properly.
- Screw the 10mm bolts back in by hand, then torque them to 7.5 ft-lbs in a criss-cross fashion to prevent pinching of the o-ring.
Step 9: Reinstall the transmission pan.
- Take your NEW gasket and insert the metal spacers.
- Reinstall the transmission pan along with the new gasket.
- Screw in the 10mm bolts by hand, but don’t tighten them all the way just yet.
- Torque the 10mm bolts to 6 ft-lbs or just slightly by hand; be sure to use a criss-cross pattern to ensure the gasket is properly seated.
- DO NOT over torque the 10mm bolts or you can create a leak in the gasket.
Step 10: Drain the transmission cooler hoses (optional)
- To drain more ATF fluid, you can remove the transmission cooler lines.
- On the front passenger side of the vehicle, you should see a transmission cooler.
- There should be two hoses that connect to a thermostat and is simply held on by a 10mm nut.
- Place a drain pan underneath the hoses, remove the 10mm nut, then pull the hoses off and allow the additional ATF fluid to drain.
- Once no more ATF fluid is coming out, replace the o-rings on the hoses via the o-ring assortment kit listed in the parts section.
- Reinstall the cooler hoses and hand-tighten the 10mm nut.
Step 11: Prepare to fill the transmission pan.
- As shown in the video, reinstall the fluid level insert and just hand tighten it using only the 5mm allen bit and no ratchet; the fluid level insert is plastic and the torque spec is 1.5 ft-, so you want to be very careful not to break it.
- Next, you will need a special transmission fluid fill adapter which can be found in the tools section above.
- Screw in the fill adapter and just hand-tighten it.
Step 12: Fill the transmission with an initial amount of fresh ATF fluid.
- Using a fluid transfer pump, attach the fill hose to the transmission fill adapter.
- As shown in the video from BleeinJeep, insert the inlet hose into your container of new ATF pump fluid into the transmission pan.
- While the ATF capacity is 10 liters, you will only be able to get around 6 liters in initially before the fluid begins to overflow.
- Stop trying to add more fluid, but keep everything connected.
Step 13: Monitor the transmission fluid temperature
- Next, you will need to begin monitoring the transmission oil temperature to fill the transmission to the correct level.
- Using a diagnostic tool such as the Foxwell NT510 Elite, connect it to the OBDII port located in the driver-side footwell.
- Turn the ignition to the “ON” position.
- As shown in the video from Scan Tool Network, select your vehicle > select “manual” scan mode > select transmission module.
- Now select “Read data stream”, then explore the various options until you find the transmission oil temperature.
- Note: If you don’t have a suitable diagnostic tool, you can use a pyrometer to measure the temperature of the oil.
Step 14: Add additional ATF and ensure you reach the correct level.
- Have a friend start the car and, with the brakes engaged, cycle the transmission from DRIVE and REVERSE while pausing at each gear for 5 seconds.
- This will cause the transmission to suck in ATF and allow you to pump in more ATF fluid.
- Pump in more fluid until you reach 10 liters or cannot add any more.
- Remove the fill adapter and allow the ATF to warm up, which will cause the ATF to expand and begin to overflow out of the drain port.
- Once the ATF temperature is between 95-104°F (35-40°C) and ATF is barely dribbling out, you’ve reached the correct level.
- Reinstall the drain plug along with a new seal and torque it to 15 ft-lbs.
- Note: If at the target temperature range ATF does not drip out, you need to add more fluid. If the ATF fluid exceeds the target temperature, turn off the engine and allow the transmission oil to cool down before repeating this procedure.
Step 15: Reinstall everything and lower your vehicle.
- Reinstall everything in reverse.
- Just hand tighten the underbody panel fasteners.
- Lower your vehicle.
- Save your old ATF in a contain, so you can drop it at your local auto parts store to recycle.
- Clean up your work area and put away your tools.
