What's the correct gear oil for the 5-speed manual transaxle?

[Far M]

Hi all -- going to be dropping my transaxle for a clutch swap and will also be changing the gear oil as I'm close to 100k presumably on the original fluid.

 

I'm having trouble figuring out what the correct part no is for the gear oil. Is it the same as the 6-speed cars? Is there an aftermarket equivalent, or is this one of those areas where it's best to stick with the genuine Porsche stuff?

 

Car is a 2007 Boxster 2.7 5MT.

Edited January 17, 2022 by Far M

[JFP in PA]

The six speeds use a different fluid than the five speeds do, and this is a place where using the factory fill is essential. Porsche uses trans fluids that are made to their specification's (they do not have any GL or API ratings), are fully synthetic products that are long lived and work very well in cold environments.  A lot of people have tried aftermarket fluids, but came back to the factory stuff after experiencing problems.

[Far M]

5 hours ago, JFP in PA said:

The six speeds use a different fluid than the five speeds do, and this is a place where using the factory fill is essential. Porsche uses trans fluids that are made to their specification's (they do not have any GL or API ratings), are fully synthetic products that are long lived and work very well in cold environments.  A lot of people have tried aftermarket fluids, but came back to the factory stuff after experiencing problems.

 

Thanks JFP. What's confusing me is that even when I'm searching for genuine Porsche fluid the sites aren't differentiating between 5-speed and 6-speed cars, which is making me wonder which part no the correct fluid is. And unless I'm misreading, even the official parts catalog has the same part nos for both?

 

Do you happen to know what the correct genuine Porsche fill (part no) is for a 2007 with a 5-speed manual transaxle?

Edited January 17, 2022 by Far M

[JFP in PA]

Not off the top of my head, so I suggest calling a dealer for the number, and ONLY buying the fluid from a dealer, like board sponsor Sunset Porsche, as there are less than honest aftermarket outlets that claim their fluid is factory when it really isn't.

[Far M]

9 minutes ago, JFP in PA said:

Not off the top of my head, so I suggest calling a dealer for the number, and ONLY buying the fluid from a dealer, like board sponsor Sunset Porsche, as there are less than honest aftermarket outlets that claim their fluid is factory when it really isn't.

 

Cool, thanks. Sunset actually has a pretty good price on p/n 000-043-305-49 (the parts counter at my local dealership gave me this one) at $30/liter, but what's puzzling me is that the parts catalog seems to supply the same part nos for "transmission fluid HYPOID" for the base 5-speed and 6-speed/S models. Is it possible the factory fill for these cars was the same for the 987.1?

Edited January 17, 2022 by Far M

[JFP in PA]

Could be. In the earlier 986 cars, the five-speed fluid was unique to the five-speed due to the alloys used in the syncros, they may have changed that in the later cars.  To be sure, I'd give them a call; Luke and the rest of the parts crew are always very helpful.

[Far M]

8 minutes ago, JFP in PA said:

Could be. In the earlier 986 cars, the five-speed fluid was unique to the five-speed due to the alloys used in the syncros, they may have changed that in the later cars.  To be sure, I'd give them a call; Luke and the rest of the parts crew are always very helpful.

 

Will do, thank you sir!

[Silver_TT]

Sunset has great pricing and provide your VIN so be sure you always get the correct parts/fluids.  Just to reiterate because I personally got burned by it so no one knows better (previous owner used RedLine or similar and took it out of the "dealer only serviced" records).  NEVER EVER EVER use aftermarket gear oil.  It trashed the synchros and internals.  Sorry for the all caps but this cost me probably $7K+ all in to fix properly and thank god I didn't have a PDK or I would have been SOL.

 

I read on the Audi and Porsche forums all the time that people say they can create their own friction modifiers to match the same as the OE formula and it drives me crazy how naïve these people are with no background in lubrication or chemistry.  This isn't like motor oil where you can take your pick (although some are clearly better than others).  This is probably one of the biggest misconceptions and areas of false information I have seen.  People trying to save $50 on fluid at the risk of ruining their entire transaxle, it drives me crazy.

[Far M]

So, just following up on this in case it helps anyone else, because it was very frustrating and I got answers all over the map from various sources.

I'm usually not at all a stickler for using genuine Porsche parts but this is an area where I chose to be conservative and wanted to refill the transaxle with exactly what it would've received at the factory, following JFP's advice. I also live in a cold climate and had read some suggestion that aftermarket fluids might be less than ideal. Ultimately, I have no idea what the differences are, or who makes the transaxle fluids for Porsche, which I understand in the past used to be specialized to Porsche specs. Hell, one local dealer told me they used Mobil 1 across the board.

Anyways, if I'm reading the official parts catalogs downloaded from the Porsche website for both 987.1 and 987.2 correctly, they both spec part no. 000-043-304-71:




(This is from the 987.1 catalog; my understanding from this is that the -204-71 part no (which incidentally also appears in the latest, 2017 revision of the 986 catalog) has been superseded by the -304-71 part no.)

Two problems:

• 000-043-304-71 corresponds to a 20 ltr container
• 000-043-304-71 shows as discontinued everywhere I looked

When I called Sunset, I got a voicemail back with part no. 000-043-305-00. Notably, this shows on their website as having replaced the -204-71 part no. Also, there were a few websites suggesting that -305-00 superseded -304-71. E.g., this from Porsche Atlanta Perimeter's parts search:




So, I could be wrong, but I'm pretty confident the correct OE part no. is 000-043-305-00. Problem is, you have to find someone willing to sell it by the liter because it's also a 20 liter container. I know Sunset does this, though, under part no 000-043-305-00sp.

(As for part no. 000-043-305-49 that my dealer gave me, I believe that's the part no. for the differential "side" of the automatic transaxle, since it's my understanding that the transmission and diff don't share the same fluid in that instance. To be clear, I believe it's also a 75W90 gear oil. It might work for our manual transaxles, but I wasn't willing to take that chance given that I could source what I'm more confident is the correct fluid.)

 

[Silver_TT]

See post #22 here:

Mobilube PTX Transmission Fluid: "Must do maintenance" for all 997s - Page 2 - Rennlist - Porsche Discussion Forums

RENNLIST.COM

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997 Forum - Mobilube PTX Transmission Fluid: "Must do maintenance" for all 997s - While I had my car on Wayne's lift the other day for the water pump project, I also changed my tranny fluid to PTX. Its one of the simplest DIY projects and based on my results I believe it's must...

 

I have never done business with this place but I noticed they said they buy the 20L and break it up into 1Ls for sale.