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Someone asked for a DIY on how to change gear oil on the 981, so here goes. No guarantees this is right, or that you won't mess something up/DIY'er beware/other disclaimer crap. Rely on the below at your own risk.
The PDK has two reservoirs, one for clutch fluid (which is NOT DIY-able due to needing PIWIS) and one for gear oil that lubricates the diff and transmission gears. This DIY covers only the latter. Service interval is allegedly 120k, but that's insane. The car sees track time, but the fluid was black, very thin for 75w90, and had some metal flakes already at 26k miles.
You'll need a torque wrench, M6 socket, M8 socket, fluid pump, 3/8 socket wrench, and extensions. Plus fluid and a drain pan, of course. Service at no more than 40 degrees C fluid temp per Porsche. Took me 1.5 hours without rushing, including jacking and lowering.
Step 1: make sure you have the right fluid. Cars with LSD need fluid with LSD additive. Cars without do not. My car is open diff so I used Driven 75w90 sans LSD (they also have a LS version, which LNE sells).
Step 2: raise car (level), remove rear wheels for easy access unless you have a lift.
Step 3: remove fill plug with pan under it. You want to start with the fill plug because you'll be pretty SOL if you drain the fluid only to find out the fill plug is jammed or you break something. It also gives you an idea of your current level. I had zero fluid coming out of the fill plug, which tells me the level was probably a tad low.
Step 4: remove rear drain plug under diff. This should release 2 quarts or so of fluid.
Step 5: remove small drain under trans (make 100% sure NOT to remove the clutch fluid drain, which is within the black plastic cover on 981's).
Step 6: Fill through fill hole using pump, after capping the drains of course. It should hold around 3 liters if you got everything out. Torque values should be around 20 ft/lb for the diff drain and fill, and 7 or 8 ft/lb for the small (m6) trans drain. Don't over tighten. It would probably be a good idea to replace the sealing rings, but I did not and so far so good.
IS IT OKAY I USED LIQUI MOLLY GEAR OIL FOR THE PDK GEAR OIL AND FRONT DIFFERENTIAL OIL? WHERE DID YOU READ TEMPERATURE HAS TO BE DEGREES?
Fluid temp requirements are in the factory service manual. No more than 40C basically means you must do it cold, not after driving around. Fluid expands with temp, so the level will be wrong if you do it super hot.
The gear oil you posted is GL5 and would be fine for PDK gear oil.
I want to tackle this job in the near future but I can’t find Driven 75W-90 without the LSD additive. Any harm in using the LSD version? Or if anyone has another suggestion, please share. The other fluid I considered is Redline 75W-90, which is also GL5 and has LSD additives, just because I already have some in the garage.
The limited slip additive does not hurt anything. That's why we only stock the one with the additive. Less changes of someone putting in the non-limited slip version in an LSD-equipped box.
Thanks for the DIY write up! Is it true that the OEM Porsche PDK fluid the same fluid used for the gear/diff and PDK transmission? I am confused as my local dealer said it uses the same fluid.
Thanks for the DIY write up! Is it true that the OEM Porsche PDK fluid the same fluid used for the gear/diff and PDK transmission? I am confused as my local dealer said it uses the same fluid.
The PDK and diff side do not sure the same lubricant. The diff uses a 75w90 gear oil and the PDK side uses a DCT fluid. Driven and Motul both offer a superior DCT fluid for the PDK side of the transmission, but of course we're partial to Driven and that's what we used in all the GTB1 and GTB3 Caymans we build at BRS.
So I have a 991.2 GT3. Ordered an OEM pan/filter and new aluminum fasteners. Service Manual states the following:
"2. Aluminum screws are secured using the yield-point-controlled method
3. Use special torque wrench 9768 for this
4. To ensure the screws are tightened uniformly, the specified tightening setting "light. medium or hard" must be used"
An initial tightening torque of 2.4 NM is called out followed by Tighten M6 screws at "medium" setting.
in all my years i have never heard of a light, medium or hard" setting on a torque wrench. If you are torquing to yield, usually there is a specified torque listed, in this case 2.4 NM followed by an angular component (90 degrees as an example) Nothing besides the initial setting of 2.4 NM is called out other than tighten screws at medium setting whatever that is. Torque wrench part number is 000 721 976 80 and lists for around 5K. Not sure what so special about it. I have a digital snap on 1/4 drive that will torque to 2.4 NM no problem. It's the medium setting that baffles me. Anyone have any additional info on torque values or method for these fasteners? Thanks in Advance.
11-06-2018, 02:17 AM
PDK Gear Oil
