I have a 2009 Carrera S w/6 speed transmission and 26K miles on the odometer. I have had regular oil changes performed by the dealer since new and have had the brake fluid changed once. The car has never been tracked but occasionally might see some short bursts of hooligan speeds on the open highway. The car may sit for a month between drives, especially during the winter, but sees more use in warmer weather (North Carolina).

1. How concerned should I be about changing out the transmission and rear gear lube? I have no shifting issues except into 1st when cold (SSK installed). Not hearing any rear end whine or such that would indicate any problems. Really just concerned about the age of the lubricants: Vehicle will be 7 years old this September.

2. If your recommendation is to change out the fluids, what are your recommendations on brand or weight of the replacement lubricants?

Thanks for your assistance.

 

AFAIK ( but check your owners manual! ) there is no call out for changing transmission/diff fluids on time.

Unlike engine oil transmission/diff fluids do not get contaminated.

So even though 7 years old seems like a long time the fluid is not due to be changed.

But of course you can change the fluids any time you want.

While not a common occurrence I can tell you I elected to have the transmission/diff fluids in my recently (this back in 2009) purchased 2003 Turbo and the tech found a selector shaft leak which resulted in the transmission being replaced under CPO warranty. Had I waited to change the fluid likely it would have been after the CPO warranty expired and I would have had to pay to have the fluid leak addressed.

I tend to lean towards an early fluid replacement. Used to be automakers called this out. For instance, back in 2001 when I bought a new Camaro Z28 just a few MY's previous GM called out a transmission/diff fluid change at IIRC 18K miles. But GM dropped that early fluid service. However, I still had the tranny/diff (equipped with an LSD too) changed at around 15K miles.

Up to you if you want to wait or have the fluid changed early.

My recommendation for which fluids to use is just whatever Porsche recommends. I see no reason to use my cars as guinea pigs to try to come up with a suitable alternative fluid. There is not a whole heck of a lot to be gained and a whole heck of a lot at risk (transmission/diff) if I find fluids not up to the task.

While your car will be a bit more expensive to have a transmission/diff fluid service done, a transmission/diff fluid change in my Boxster is one of the least expensive dealer services available. Labor is just 0.3 hours and the while the fluid can be "expensive", often times I get a discount on the fluid. One time I got the fluid for just $5/liter as the dealer had extra left over from warranty repairs.

My Turbo is a bit more expensive. More labor is required to expose the transmission and I think its 6-speed requires a bit more fluid. Still the service is not a wallet buster.

But in the overall cost of keeping the cars on the road the cost of periodic transmission/diff fluid services is way down the list.

My 2003 Turbo has over way over 100K miles on its replacement transmission/diff (and over 142K miles on the original front diff -- AWD you know) and all are just fine. Periodic and a bit more often than what Porsche calls for fluid services I think (like to believe at any rate) help account for this.

My 2002 Boxster has its original transmission/diff and the car is just a few hundred miles short of 300K and the tranny/diff are just fine and probably can go another 300K miles. Again periodic and a bit more often fluid services than what Porsche calls for have been done and have played a role in the hardware's long and trouble free service life.

If the Porsche fluids were subpar I think neither transmission would have lasted this long.

 

iirc porsche suggests 90k miles for trans oil changes which is absurd and means you'll have parts that require attention sooner than if you adhered to a far more liberal oil change interval. i think 50k miles is much more like it, and if you 'track"? even sooner way sooner.

i just changed mine ( 2nd time after a gearbox refresh of a cpl years ago ) which means i'm probably at 35K miles on this fresh flush. it came out still looking like golden honey and i use exclusively M1 Delvac 75/90 withOUT any "friction modifiers" since i am running rwd.

for a stock car i'd use that or redline 75/90 is also GREAT g'box oil for the car. once changed, you should no longer have that momentary difficulty getting into 1st while the motor is still cold. fresh gear oil does wonders and you'll be rewarded also with butter smooth shifts.

 

Use only Mobilube PTX available from SunsetPorscheParts.com. Do a search for Mobilube. Using anything else will be a disappointment. You need exactly 3 liters assuming you don't spill any.