[HOW-TO] PDK Fluid change
 

Almost at 100k miles, 160k km and decided to change the PDK fluids over the weekend. It was all done by a local indy shop, cost for labour $100

parts needed:

• 6 liters of Pentosin FFL3 - P00004330513 (1L packaging) -> Transmission Fluid_FFL-3_2017_COLOR.pdf in attachment
• 3 liters of Mobilube PTX SAE 75W90 - P00004330549 (1L packaging) + 400ml or so if you decide to drain the differential
• Transmission Pan/Filter Kit PN: 9G1.321.025.00

Tools:

• Autel - MaxySys to get the PDK into fill mode.

I used a lot of information from this thread, and this post.


Wet Clutch fluid (Pentosin FFL3),

1. more details in "WM 370235 Checking and topping up ATF (clutch fluid).pdf" and "WM 370255 Changing ATF (clutch fluid).pdf" attachment
2. procedure is simple, remove the drain plug on the plastic Transmission Pan and drain the fluid.
3. remove 13 aluminium bolts carefully as there is still some fluid left over in the pan.
4. Install new Transmission Pan, torque the bolts to 2.7NM(24.0 Inch Pounds).
5. add Pentosin FFL3 until it starts overflowing from the fill hole.
6. Start the car
7. kick PDK into fill mode using Autel, transmission has to be between 30-40 C to go into fill mode and add more until it start overflowing again.
8. replace the fill plug, torque to 26.0’ +/- 2.0 Ft-Lbs

Although the specifications say 5.2 liters, I managed to only get 5 liters in... dunno why

Gear oil:
All good info on the 997.2 thread apart from Gear oil fill hole is on the opposite side of transmission.

1. Drain Mobilube, I have drained an additional 400ml from the differential. Diff drain plug is smaller and to the left of the green circle in the below photo
2. Replace the drain plug, torque to 26.0’ +/- 2.0 Ft-Lbs
3. Add Mobilube through the fill plug(in the area of the green circle on the below photo) until its stats overflowing.
4. if you have decided to drain differential as well, start the car once you fill it in and go through the P/R/D shifts and let the wheels spin in the air to fill in the differential chamber and check the level again
5. Replace the fill plug, torque to 26.0’ +/- 2.0 Ft-Lbs

https://cimg3.ibsrv.net/gimg/rennlis...64caa5fe20.jpg
This is the location of Drain and fill plug. Fill plug is hidden behind the crossmember. Sorry, didn't think to take another photo

I hope this helps someone , if you have any question feel free to ask them.

I like my DIY skills but this is one service I'm going to take it in for. :thumbup:

when should it be changed - miles, years ?

The documentation for the 991.1 states 120,000 miles or 12 years.

it states 180,000 km, but what worried me was a 2nd -> 1st "clunk" on cold and the fact that same PDK in 997.2 had wet clutch fluid scheduled at 100,000 km(60k miles).

2nd -> 1st clunk is now gone, and it didn't break the bank doing it at indy shop

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hey, its your car , your choice... issue here was that when I asked the dealer for it they had no idea what I was talking about.... apparently no one in this region has done it before :)

its not difficult, only issue is finding the shop that has a compatible diagnostic tool to kick the PDK into fill mode and cooling it down to 30-40 C. when outside temperature is 34C it can be a challenge.

Maybe send a sample for testing (Blackstone or other reputable laboratory) at 60K miles before going all the way out to 120K. Personally, I would send a sample off for testing prior to warranty expiration, so you have documentation if there are unusual amounts of metals in the sample.

I thought pumps were needed to do this job. Definitely above my pay grade.

I think that's covered in this step:
Tools:

• Autel - MaxySys to get the PDK into fill mode.

I will be doing this in the near future to a 991.1 TTS and I have a few questions:

• What are the drawbacks of not setting the PDK/final drive in fill mode? Will making sure I refill the same amount as I take out not enough? Or doing the top off process and making sure it is filled enough?
• Does anyone recommend using another 70W90 oil besides Mobil? Maybe RedLine or Motul?

Also, if anyone is doing the final drive, attached are the pages from the workshop manual:
399055 CHANGING OIL FOR FINAL DRIVE (WITH TRANSMISSION OIL)
399035 CHECKING AND TOPPING UP OIL FOR FINAL DRIVE (WITH TRANSMISSION OIL)

On prior cars I have had great success with Motul Gear 300 75W90

I too asked my dealer about it and they said it was a sealed trans. No need to change the fluid.. :confused:​​​​​​​

I inquired with my dealer about this today. They wanted about $1100 to do fluid + pan/filter

They also proposed a “drain and fill” without replacing the pan for about $600 which I am considering. The fluid is pretty expensive, especially the Mobil Lube for the gearbox.

My car has 34k and is 8 years old, transmission shifts good. I doubt I will own it at the 12 year mark when it is advised to replace it but I do want it to run its best for the rest of my ownership.