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This weekend I decided to change the rest of the drivetrain fluids, as well as another transfer case fluid swap, and boy was it a bit surprising. Fluids used: Royal Purple Synchromax (manual transmission), Royal Purple 75w90 maxgear (both diffs), Ravenol TF0780 (transfer case) FYI manual transmission and rear diff service essentially requires a fluid pump Here is an overview of the fluid condition as removed, versus new fluids behind them (both diffs use the same 75w90 royal purple). Notice the hue of the transfer case fluid which was changed only 2 weeks ago. It did not have the distinct burnt smell of the original fluid, but it was now opaque with suspended friction material. The transmission and gear oils were in fairly good condition, if not a little darker than I expected. No burned odor. I poured some of the original oil (likely Porsche OE) versus the 2 week old Ravenol, and you can clearly see the burnt original fluid with clutch material, however even the new fluid was dark with additional friction material in suspension, leading me to believe that there is still significant amounts of that in the case. I believe that after a change the remaining material in the case is distributed over a short time and reduces the effectivity of the fluid (I was noticing slightly more hesitation at the end of the 2 week timeframe). I am considering trying to perform a flush with a gear pump or compressor to remove this buildup, however I am not sure if a solvent or traditional transfer case flush fluid would be harmful to our clutch discs.
Year Model Mileage Location AT/MT Fluid Remedy ForumUserName ------------------------------------------------------------------------------------------------ 2012 V6 105,000 TX, USA MT Raveonl TF0870 Y ChrisFu Stumble through 3rd and 4th (similar to a misfire) plus binding/pulsing during low speed high steering angle driving. Fluid change showed very dark, likely burnt oil. Post replacement, 90% of symptoms eliminated - very slight intermittent "slip" feeling at high torque/high RPM in 2nd. Will be replacing all other transmission fluids shortly.
Our Cayenne is a northern one owner vehicle (Beachwood Porsche - Cleveland) that we only recently purchased in Janurary @ over 100k miles so it likely hasn't seen much for hot temperatures. I would bet its simply from a lot of highway mileage (supposedly) over the past 5 years the original owner put on it.
Good analysis Don. I'm very curious to see the visual condition of the oil on vehicles who are experiencing symptoms at mileages as low as 25-30k as I have seen on other threads.
I don't think Redline D4 has the proper friction modifiers for the clutch pack transfer case, and I dont see TF 0870 compatibility listed on the specs. So maybe dont give up hope just yet; I'd try another change with Ravenol TF 0870, Porsche 000-043-301-36, Porsche 000-043-305-63, or Motul DTCF and see if you note an improvement.
Good news to report; I appear to have the same success! Immediately after the fluid swap I took the Cayenne on a spin to a local industrial park and first of all noticed nearly no detectable stumble through 3rd and 4th (a new experience for me in this car!) on the way over. I followed that by tight figure 8s through a commercial parking lot for 10 minutes or so with no binding, lurch, shudder or anything. This appears to have remedied the 90-95% symptoms immediately, so I guess I will wait with bated breath to determine the longevity of the fix. Below you can see the immense difference in new fluid color versus what is probably the original lube after 109k miles. Also, the Ravenol bottle actually has a very handy dispenser that I used in lieu of the OTC Syringe (the tubing included with the syringe was actually too large to fit into the inspection plug hole, whereas the Ravenol was a smaller OD and fit perfectly).
The smell is definitely of "toasted" hydrocarbons, but not as "burnt" as I have smelled from some really bad differential oil changes before (smelled up my whole garage for a week). That being said, those were totally different gear oils as I have never drained an automatic transmission or gearbox that used ATF prior to this so maybe it is indeed on the same level. ill try to snap a side-by-side of the new oil vs used this afternoon. Also likely going to send some to Blackstone.
Cayenne is 2012, purchased from a very high volume Porsche dealer cross country and shipped (we never test drove it, first time Ive ever purchased a car this way). Sure enough, I noticed the bucking problem right away, however it was slight at the time and has progressively become more noticeable. Strangely enough some days it almost disappears, and some days its rather extreme. Does not correlate with ambient temperature, drive duration, or any other factor save perhaps extra low speed steering time seemed to exacerbate the problem this weekend. Drained the fluid tonight and have images below. I have seen and smelled worse, but this is pretty dark stuff. No large visible particulate in suspension based on a drip curtain test.
Well count me in, thanks to this thread I am fairly sure we have a failing transfer case on my wife's recently purchased 1-owner 958 V6 6MT (105k miles - her dream car since shes a manual lover like me and cant buy a decent stick SUV anymore). As I was unfamiliar with Cayenne drivetrain issues, my research made me believe our symptoms were that of the 955/957 cardan shaft which is a thankfully much less expensive fix. Reading the descriptions here and I am almost certain its transfer case related instead. Slow speed sharp turns result in what feels like a truck stuck in 4WD low maneuvering in a parking lot, a significant binding and noisy feeling. In a straight line the effect is less pronounced, more of a thumping hesitation in 3rd and 4th gear during harder acceleration, however essentially undetectable in 1st/2nd and 5th/6th. I had planned on taking it in tomorrow for a diagnositc at a local Porsche shop, but now will try a fluid change (Ravenol TF-0870) tomorrow instead https://www.amazon.com/gp/product/B00QCVP6UK/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=A3NWHGHN360KCD Will report back with any results. Any tricks to the fluid swap? Seemed pretty straight forward in the service manual: Elevate car, remove top plug, remove bottom plug, drain until empty, then refill.