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Discussion Starter #1 (Edited)
Hello,
I changed my PDK transmission- and differential oil.

Here is the how to:

Explanations:
The Porsche 911 (991.1) PDK gear box has two oil reservoirs.
One for the clutch and transmission, the second for the differential.
For the clutch and transmission you need 5,2l Fuchs Pentosin FFL-3.
For the differential you need 3l Mobil Mobilube PTX 75W-90.
.............
update needed


Josch
 

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Nice; how many miles on it - I agree but why the change
 

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Gear/differential oil can be changed statically.

You cannot get all the clutch fluid without a PIWIS and the engine running. YOu cannot get more than half the fluid that is in the clutch itself as the drain holes are in the center shaft and there is no way to get to the fluid and the old fluid stays in the clutch. It has been reported by other people attempting this that they only get 3L of used clutch fluid out, so you are only getting 60 percent of the clutch fluid changed. You can change it, run the car to mix the old and new fluid, repeat fluid change and drive two more times to get to 92 percent fluid change. Pricey. Need at least 10L FFL-3 at over $20 per Liter.

V6
 

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Discussion Starter #4
Hello V6,
what you describe is the procedure to change oil for a automatic gear box (torque converter). Here you really need a PIWIS and a double oil exchange. A PDK oil exchange is similar to a normal manually gear box with the difference that you have two oil reservoirs for clutch/transmission and differential (transaxle).
Also the official Porsche garage procedure describe exactly 6l Pentosin oil and 3l differential oil and re-new the 3 caps.
 

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Hello V6,
what you describe is the procedure to change oil for a automatic gear box (torque converter). Here you really need a PIWIS and a double oil exchange. A PDK oil exchange is similar to a normal manually gear box with the difference that you have two oil reservoirs for clutch/transmission and differential (transaxle).
Also the official Porsche garage procedure describe exactly 6l Pentosin oil and 3l differential oil and re-new the 3 caps.
My comment was to say that your original post implied (or missed information) that could lead someone to do the clutch fluid change without a PIWIS.

The PIWIS is required so the internal valve body/Mechatech unit can be put into oil change mode and the running engine turns the clutch oil pump so the clutches can be emptied. If you don't do that, the clutch remains at least half full that will not be drained out, leading to less than the factory fill amount when refilling.

There is a thread on Rennlist where someone actually did a static (non-running) FFL-3 fluid change. Because significant old fluid remains trappped in the clutch, he only got 3L out and to reach full, only added the 3L back in. My comment on running the car and repeating the drain and fill two more times was so that 92 percent of the fluid would be new after the third fill. 3 drain/refill cycles times 3L per static fill attempt = 9L needed. I was not saying that was the total fill. A user can do a reasonable clutch oil change if they are willing to do it three times (with some driving in between to mix fluid so some old fluid drains out each time). However, the fault with this is that the PIWIS is needed to set proper fill level. The Rennlister measured how much came out and put the exact amount back in. This works if the transmission was filled at the factory correctly and did not loose any fluid up to that point.

My 981 Cayman had its gear oil and clutch fluid changed last fall. The dealer used a PIWIS and still only got out 4.5L of its rated 5.2L fill.

V6
 
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