Did mine a few weeks ago. Definitely smoother. The biggest difference I notice is I don't need to blip the throttle as hard when rev matching because the revs are a tad slower to drop when changing gears. It's far easier to rev match now. Well done Bruce!

 

I've ordered from suncoast and will be doing this soon to my 9800 mile C4S. No shifting problems noticed, but if a change helps prevent any future balkiness in shifting, I'm supposing that will be better for the life of the transmission.

Why in the heck are the plug seals so expensive? $13.xx- I tried to argue that they were the same size as an oil drain plug washer, but the nice guy at Suncoast was convinced that they were indeed different in some way.

 

About to order from Suncoast, and it sounds like I should get the seals as well as my local Indy claims they rarely do this. I've been advised to get 4 litres, but Suncoast has told me most only order 3 (997.2)?? And, I had contacted Exxon/Mobil to see if there is anywhere I can get the PTX in Canada and was told it's not sold anywhere on the NA continent - could Suncoast be working off an old supply?? Thanks,

 

Same quantity for 997.2 and 997.1 gear oil change. 3 liters. Sunsetporscheparts.com has the best price on the Mobilube PTX. Search for PTX. $28.23 per liter. The two plug seals are exactly the same as the oil drain plugs.

 

I did this change yesterday in my C4S. Had the car up on my Kwiklift and then had to raise the rear of the lift by a couple more inches so that the ramps would be level. Drained until the last drop was out, then filled using the lower, forward, fill hole.

Using the three bottles that I got from Sunset, they all went in, without overflowing. Sure, maybe there was .1 litre of oil total left behind in the three bottles, but it bothered me a little that it didn't begin to drip out of the fill hole indicating it was indeed full. Finger test seemed to confirm the fluid was up near/at the opening, so I guess it's OK?

 

Nice work! Three liters is perfect. Happy Fourth.

 

I feel like this thread is a bit of a bandwagon to jump on.

I did this maintenance and the results are pretty good when the tranny is fully warm, but marginal when cold. Wanted to post an update and say that while this is pretty easy to do it did not make a massive difference in my 997.1 X51 C4S

mreloc- I had the same experience on fill volume, 1,000 miles later all is working fine

 

No bandwagoning here. Fresh trans oil change with the other stuff did nothing for jamming going into first. A change to PTX several thousand miles later immediately fixed it and it has remained fixed.

Perhaps people who are not seeing a bit of difference already had PTX in there?

 

I guess I was over zealous on preventive maintenance and decided to have my highly respected Indy change the gear oil with only 24K miles on my 2008. No problems other than some stiffness getting into first at a traffic light.

The indy used Redline synthetic 75/90 and now the shifting is much stiffer and no longer smooth. I was disappointed and wondered why I decided to change the fluid which Porsche says lasts 120K miles. The Redline gear oil is the stuff they use with the race cars they build and support. I am sure nothing will break with the Redline gear oil but really knows. I am surprised as to how different brands of gear oil affect the shifting on our cars.

This Indy is a great company and since I was concerned, they said to bring it in on Thursday and the gear oil will be replaced with PTX. Hope to have a smooth shifting tranny once again.

 

I think that may be correct. Although I've only driven a handful of miles, the difference on my 10K mile transmission couldn't be detected. It was pretty smooth beforehand. One thing I'll note, however, is that even at 10K miles, the drained fluid was fairly cloudy (and the drain plug had a little gray sludge in it) so I think refreshing the fluid was a good move, regardless.

 

Reached the 6 year point...so took it in for scheduled maintenance (engine oil/filter, brake fluid, all wheel drive controller oil, and the front differential oil change)...and after reading this post, I also decided to have the transmission gear oil changed over to PTX. Wow, what a difference! The car definitely shifts much smoother (especially 1st to 2nd when cold) and the engine actually sounds smoother and tighter (if that makes any sense). I don't believe that Ive ever experienced as much change in any of my previous cars simply by changing the gear oil. Thanks Bruce for starting this thread!

 

I think the issue with 1st gear jamming is that the fluid is simply worn out. Porsche said 120K miles, but I think they just have it way wrong and it needs replacement way earlier than that. 60K? 70K?

PTX is specially formulated and denoted in my manual as the fill... and is formulated differently than all the other stuff.. .Delvac, Redline, whatever.... and most dealers simply don't use PTX and I don't know why.

Replacement such as at 20K miles shouldn't do anything.... unless time wears it out too. I hate to see someone replacing the fluid with expectations of something "better" happening, but I replaced it to address a specific problem, a super annoying jam going into 1st gear and for that, it just worked.

Peace
Bruce in Philly

 

Ive experienced the 1st gear jam once in a while...maybe once every few months (although this car is only driven about 3 days a week and even then, only about 5-10 miles per day).

However, like others have experienced, the car feels notchy when shifting, primarily after cold start up and when shifting up/down between 1st and 2nd gear (a common occurrence with these cars I'm told). However, after changing the transmission oil (to PTX), the car now shifts much smoother...and after also changing the all wheel drive controller oil and the differential oils, it also runs and sounds different, much smoother!

Not sure if the transmission oil is milage AND time sensitive (i.e. ~6 years if you suspect that the transmission oil might be better off being changed after 60K miles).

 

Just swapped out for PTX, and I must say the difference is notable but not dramatic. No idea what was in there before. And, I just like the idea of having some fresh oil in there after six years along with a chance to have a look at the drain.

 

For what it's worth. I was having problems with very "notchy" gear changes and even missed shifts on track-days. I decided to try changing the tranny fluid based on this thread and after 2-3 weeks it is much, much better. Conversation with my indy went something like:

Me: I guess choice of transmission fluid can be one of those "religious" subjects, right?
Mechanic: Yup
Me: And whatever it is you use is the only "right" transmission fluid and I shouldn't try to convince you otherwise?
Mechanic: Correct. It'll be $195 and we'll have it ready this afternoon.