I’m at 150k miles and way beyond the 16 year recommended service internal.

I’ve read a couple threads on procedures for transmission fluid changes and while it appears relatively straightforward, I’ve been advised to take it to the dealer or an independent to have them do it given some specific procedures that are recommended by Porsche (e.g., durametric temp monitoring, specific gear run throughs, etc.)

Anyone have an idea of how much an independent and dealer might charge to have this service done?

Thus far, knock on wood, the transmission shifts quite smoothly and cleanly — I’m a bit worried that doing the service (look like for the first time) — may dislodge some varnish or particulates that have accumulated and stuck to the valve body over time and will be lodged loose… resulting in an ironically WORSE shifting transmission than I currently have…

I suppose one could always do another fluid change?

Thanks!

 

I got a quote for 300 - 500 € with diagnostics and dynamic oil change, depending if I want to do diffs as well.

 

depends if they use OEM porsche fluid (which is $40+ a liter) or something like mobil 3309 which is rumored to be identical that's <$10 a liter. X9 liters

 

Well, I just paid $400 USD to have the fluid drained and re-filled. The bolts holding in the transmission pan were so rusted (was a NE car) that the Indy was concerned about bolts breaking and having to drill each one out (and the cost / risk associated with having to do it, free hand no less). Would have been ideal to replace the filter, but oh well. At least the fluid, when draining, did not look bad or unreasonable.

So far, knock on wood, transmission seems to be shifting about the same as it was before — which is to say — without any any jerkiness or hesitation. 😅

 

Local shop in SLC, Utah, quoted $900 in parts and labor for tranny service, back in June ($400 in labor which seems high, and the rest in parts). AllData calls this a “b” skill level job and says 0.6 hours is standard, which seems low, given it takes 10-15 min to come up to temp which is needed to set the right fluid level.

having said that, if you are on the fence, IMHO $ is better spent on DIY with this one. Of course everyone has their own calculus on that. I’m paying a shop for some things I could DIY b/c a) there is snow on the ground meaning it would suck in the driveway and I’d rather go skiing, and b) family might divorce me if I keep working in the truck instead of x-mas lights, etc.

“gear run-through” is I think as simple as foot on brake, not moving, move between P,R,N,D a few times. Maybe manually shift up whatever tiptronic will let you while stopped and not moving? (Experts feel free to correct me).

more-thorough fluid changes would ask for draining the lines to the thermostat, opening the thermostat, etc. but as I understand it, just draining what is in the pan and doing the filter, is regarded as sufficient.

but this one is rather straightforward to DIY, and if you use FCP Euro ($200 kit) you can do it multiple times “for free” which you may want to do given the age (at least twice over a few thousand miles?)

the temp can be checked with a $20 thermal gun, like you might have in your kitchen for BBQ for checking temps (like this / no affiliation- https://a.co/d/2qENALk)

I used a Foxwell nt530 ($180 ish), which I find to be much more useable than durametric.

I used a motiv power fill to get the fluid in there, and subsequently for other jobs. ($80).

oh and an AllData subscription ($20).

so by my math it is roughly an hour of not-hard grease time, breakeven cash the first go-around, and “free” plus labor next go-around.

I also did the tsfr case and diffs while it was up on ramps in my driveway. I’ve done all the fluids twice now, which seems like a good idea at 84K and 13 years on my new-to-me truck.

and I am much more self-reliant (at least feeling that way), when it comes to this beast I plan to venture Offroad with in the future.

 

thanks for the detailed response and encouragement. I was keen to do it on my own (as I’ve done all the other fluids) but I am glad in this case that I went to a shop.

The new to me 955 CTT was a NE car until I owned it and the amount of rust on the transmission pan bolts meant the shop (recommended by PCA group) did not recommend trying to remove as they feared breaking screws… which would then mean full-send on drilling out other screws… which becomes a bit dodgy free hand (given the orientation) and time consuming (ie expensive)

but yeah, up until that point, i was in the fence having watched professor YouTube and perused the forum.

bummer. But sort of glad I didn’t try to force it myself and then wind up proverbial s#it creek with no paddle!

 

Have the adaptations been reset?

 

ohh am I supposed to do that? Assuming I did not do that with a tool, do they work themselves out after some miles regardless?

(I know the boost adaption [sic] was a PIWIS-only special function, FWIW.)

 

Ask the shop if it was done

If not I am saying yes do it

 

thanks! I asked the shop (myself with my DIY cape), and this was not done.

I’ll check to see if the Foxwell can do it.

otherwise, will this adaptation stuff sort itself over time?

 

good question. No idea. I can ask. Or, can I do it myself with a foxwell?

 

I've already done my front and rear diffs and transfer case on my 09 CTTS Almost at 50k miles, and I'm going to do a drain and refill on my trans fluid here shortly. No leaks or issues and plan to keep it that way.

 

A fellow Rennlister sent in a sample of the Porsche OEM fluid and a sample of Toyota Type IV fluid to Blackstone. Blackstone said they are chemically identical. Clean out the pan, clean the magnets and run the bolts for the pan through a polishing tumbler to make them shiny again. For the trans fluid, I bought 10 liters in bulk, in a bucket I provided, from my local toyota dealer. $44 including tax. Got the filter and the pan gasket from Roger at 928sRus. Filled it with the same fluid fill tool described above. Torque on the filter is 10nm, torque on the pan is 10nm, torque on the fill bolt is 70nm. Torque on the drain bolt is 25 nm. Use a new crush washer.

I also put in two new wiring harnesses internally in the transmission as mine was leaking internally and pushing fluid into the wiring harness, most likely like everyone else's high mileage/ old cayenne is doing now. Can cause real problems down the road.

Also, I posted earlier about the replacement for the two harness side plugs (female) that anyone can replace themselves for cheap instead of a new body harness like porsche wants. I mean, I can't be the only one breaking these plugs taking them off to clean out the trans fluid inside of them. All you need is a depinning tool kit and you can replace them for less than $25. One is a headlight plug for a jetta and the other is the fan controller plug for a jetta (02 and up). Very common parts. See my thread. https://rennlist.com/forums/cayenne-...ess-plugs.html

 

Will you be using the trans cooler approach? https://rennlist.com/forums/diy-caye...atf-flush.html

 

meandering a moment off topic… do you happen to know what I might use to replace the car-side headlight plug, the car-side horn plugs, and the strut-side level sensor plug on a 957, or how one might go about identifying those?

I find it astonishing that these damn automotive plugs are so differentiated and yet still all basically 50/50 on if you can unplug them without destroying them in the process.