jphughan

Has anyone who has either DIYed this or who has access to PET advise whether the GT4's gearbox drain and/or fill plugs have washers that should be replaced? The PDF says there may or may not be washers. If there are, do the gearbox plugs and washers happen to be identical to the plug and washer used for the engine oil drain? If so I'll just order a couple of those from Suncoast since they stock them.

ExMB

Whats the reference to the homemade dipstick in that document? No further text on how to read it.

r553

The reference to the dipstick is for the 5 speed trans axle. Thankfully the 6 speed you need to have the oil coming out of the fill hole and you are good.

The gear oil from PET is Mobil 1 Mobilube PTX 75W90 liter bottle

P/N 00004320420L .

Sun Coast is the only source I've found for the liter bottles. You'll need approx 3.2 liters. PIWIS is not required.

Both applications use a crush washer. I'm going to install magnetic drain plugs.

Engine drain plugs

P/N 900 123 106 30 sealing ring 18 X 24

P/N 900 219 020 31 screw plug M 18 X 1,5

The Spyder PET is incorrect on the trans axle drain and fill plugs. They are not M18 and they are made of steel.

jphughan

Typically it's just a paperclip bent into a J shape and you just dip the short end of the J into the fill hole with the horizontal part resting on the bottom of the fill hole. That will tell you how far below the fill hole the fluid level is.

So the instructions in the PDF for the 6-speed about filling it to overflow, waiting 10 minutes for it to level out, and then filling to 2mm below the fill hole don't apply to the GT4's gearbox?

According to GTGears, the OEM gearbox drain plug is magnetic, but I'm not sure about the engine oil plug. I'd completely forgotten about that, although it looks like they share a common part number? If so, it sounds like we'd be good to go just ordering the drain plug that Suncoast lists. And out of curiosity, what is the 24 dimension on the sealing ring description?

r553

I bought a spare Porsche trans axle drain plug to be sure of the thread size. It is steel. Of course the Spyder PET is wrong: the trans axle drain plugs are M22 X 1.5.

As for filling this is what AllDataDIY says:

Use manual metering pump WE 1372 to fill in transmission oil up to the lower edge of the filler opening.

jphughan

Awesome, thanks!

cmosman

Attached is what the OE manual says:

jphughan

Thanks! Ok, so just top it up and definitely replace the sealing rings. Perfectly clear and easy.

Although this indicates that the plugs are M22, not M18 like the part numbers mentioned above. Which are they? I know this PDF is for the regular 981, but I thought the transmission is essentially the same. Would Porsche really have just changed the plug size?

r553

I'll let you know about drain plug sizes in 200 miles when I change my trans axle fluid.

cmosman

Per GT4-PET, replacement gear oil is: 000.043.204.19

000.043.204.19
Shell (Transaxle)
20-liter container

999.917.546.00
Shell (Transaxle)
1-liter container

000.043.204.20
Mobil (Mobilube PTX)
20-liter container
Can be mixed

Attached the OE service document.

jphughan

Hmm, that doesn't line up with this post in the Gearbox oil thread:

But it does at least indicate that Suncoast's generic manual transmission oil is Shell's: http://suncoastparts.com/product/99991754600.html

Also, part number relationships corroborated in this post containing the text of a Porsche bulletin: https://rennlist.com/forums/996-foru...ml#post8226081

cmosman

Shell Transaxle was renamed to Shell Spirax S5 ATE. Data sheet here.

For those ready to guinea-pig their transmission, the internet considers these equivalent (your mileage may vary):
- Castrol Syntrax LongLife 75W-90 GL-5
- Liqui Moly 75W-90 GL-5
- Fuchs Titan Sintopoid 75W-90 GL-5

ExMB

I'm not sure I would take a 17 yr old tech info with allowable replacements as valid just because 1 part number matches up. Changes have happened. When I checked with my dealer they haven't received an approved substitute similar to the listing they had for 987.2 mechanicals.

r553

Today I pulled the trans axle fill plug and it is an M22 X 1.5 steel plug. My dealer's Spyder PET listing is incorrect calling for an M18 X 1.5.

jphughan

Thanks for the update! Is the drain plug the same? And do you happen to have correct part numbers for the plugs and crush washers?