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About what I deduced, looking at the drive system with an iCarScan. The transfer case oil change can be reset with the iCarScan. There is a function in the iCarScan to initiate a calibration. I couldn't get that to work -- but admittedly didn't pursue it a bunch. Let me rummage through my pics and see if I can illustrate some of this.. hang on..
That's the result of trying to do the forced calibration. The instructions on the first page giving conditions for this to happen aren't really clear to me - but it appears it must be done with the vehicle moving very slowly, and with the engine providing some drive power. That pretty much makes sense since that would allow the sensors on the driveline to get real signals of things like wheel speed and let the controller for the AWD learn the setting for the transfer case clutch. I did try doing this while driving it slowly - but that was really pretty dangerous, and I didn't have a second person handy to trigger it while I drove the CTT..
So - I was a bit concerned about that - until I saw that the system apparently does a calibration quite regularly by itself - no trigger needed:
Looking at the above - it appears every 155km - the unit does a calibration all by itself. Dunno if it's based on distance, or time, or number of start cycles.. but it appears to do it quite frequently.
Given that - it would be nice to teach the vehicle that it has a new case and to have it calibrate the new clutch - but if you don't - I suspect an automatic calibration is done fairly soon so you should be good.
Huh. Had occasion to swap my battery on Saturday. The thread on that was great so thanks to whomever for the assist. I elected to let the power die when finally I got in there. Funny thing is I lost no regular memory functions - seats, radio, windows, etc. However, upon first run it was clear my transfer case symptoms were GONE. I had changed fluid a second time after 500 or so miles to no avail at all really. I've driven a couple of 45 min drives in traffic and around town and it's a totally different experience. I'll obviously be keeping a keen eye on it but I was not expecting this at all. Maybe I'll pull the neg cable as routine maintenance going forward.
Huh. Had occasion to swap my battery on Saturday. The thread on that was great so thanks to whomever for the assist. I elected to let the power die when finally I got in there. Funny thing is I lost no regular memory functions - seats, radio, windows, etc. However, upon first run it was clear my transfer case symptoms were GONE. I had changed fluid a second time after 500 or so miles to no avail at all really. I've driven a couple of 45 min drives in traffic and around town and it's a totally different experience. I'll obviously be keeping a keen eye on it but I was not expecting this at all. Maybe I'll pull the neg cable as routine maintenance going forward.
I've observed the same thing if I clear the transmission adaptations. My WAG is - letting it power down cleared them on your Cayenne. I suspect the transmission tries to adapt to the slippage that occurs in the transfer case - and doing so - makes the slipping worse. Clearing the adaptations means it's shifting by the "map" in the transmission control unit - which apparently is better matched to a slightly slipping transfer case than one that has adapted to it.
I've observed the same thing if I clear the transmission adaptations. My WAG is - letting it power down cleared them on your Cayenne. I suspect the transmission tries to adapt to the slippage that occurs in the transfer case - and doing so - makes the slipping worse. Clearing the adaptations means it's shifting by the "map" in the transmission control unit - which apparently is better matched to a slightly slipping transfer case than one that has adapted to it.
I've observed the same thing if I clear the transmission adaptations. My WAG is - letting it power down cleared them on your Cayenne. I suspect the transmission tries to adapt to the slippage that occurs in the transfer case - and doing so - makes the slipping worse. Clearing the adaptations means it's shifting by the "map" in the transmission control unit - which apparently is better matched to a slightly slipping transfer case than one that has adapted to it.
Go figure..
So after 5 days on the beach in Mexico, I have come to agree that this is quite possibly the case. Mine doesn't do it when first driven off, only when warm. If Porsche is anything like BMW (and I'm assuming all other cars as well), everything is set to a standard for the first minute or so after a cold start, then the sensors start taking over.
I'll attempt to reset my transmission and see what happens. However my transfer case is like bread in the toaster; it's not quite toast yet, but damn close.
I had mine into the dealer to check the TC the other day.. (at 85,000 miles of a 100,000 mile warranty) they came back and told me it was fine.
It probably is -
They couldn't feel anything or hear anything, so they drove it - then they brought it back and did the acid test - disconnected it from the AWD controller - and drove it again. It felt identical. That's probably a worthwhile test if you're doubting your transfer case. Mine felt lumpy when I got back from California where I'd changed the oil (hi Jay!).. but after a few days of driving around in NJ traffic - it didn't really feel that lumpy again. Shifts were smooth again. I had the same experience on the way out to California, then driving around in LA. It started to feel lumpy driving around in LA. Changed the TC fluid and it felt OK again.
My WAG - some of the people who are feeling transfer case issues (rough shifts) - are actually experiencing the transmission adaptive settings being wrong for the driving environment they are in. Going to and coming back from was mostly open highway, sometimes at speeds in excess of 80 mph for hours at a time. Had that going out - then I got into the stop/go traffic of LA and it didn't feel "right".. after a few weeks in LA it started to feel better, but I did the TC fluid change anyway. Coming back to NJ - same deal. Long stretches of sustained high speed driving, followed by stop/go driving. My guess is the adaptation sets lower RPM shift points in the map for the transmission due to the long sustained stretches with no shifting. Then you get in a city/urban environment, and it feels rough because the transmission is upshifting at lower RPMs than is ideal for that sort of traffic - until it relearns the new driving environment.
My other yardstick on it was the 2018 Cayenne Platinum edition loaner I had (4,000 miles on it..) Despite the smaller engine - it felt a bit harsher shifting than my Turbo does.
Next time it starts to feel off - I'll plug the iCarScan in and try clearing the transmission adaptations (give it amnesia) and see what happens. Based on what I have observed - my WAG is it will feel fine after doing that.
BTW - I've gotta find out if it's possible to add "Sport Plus" to the '11 Turbo. I rather enjoyed the performance of the loaner once I found that button..
SAVING FOR TORQUE REFERENCE - Installing 955 transfer box torque values and instructions
1. Support main transmission on converter bell housing with a wooden block -arrow- .
2. Gradually run in transfer box. Press vent line into holder -arrow- and attach to transfer box.
3. Screw in fastening screws on main transmission. → Tighteningtorque: 33 ftlb.
4. Tighten holder -A- for Tiptronic line using fastening nut -arrow- . → Tightening torque: 7.5 ftlb.
5. Support transfer box with transmission jack and remove wooden block between converter bell housing and suspension subframe.
Note Always observe the exact work sequence when installing/removing the transmission cross member.
Note Screws which are tightened with a torque angle must be replaced with new ones.
6. Install transmission cross member
7. Screw in two cross member screws -B- on transfer box holder. →Initial tightening: 37 ftlb. → Final tightening: 90 °
8. Screw in fastening screws for securing transmission cross member to body -A- . → Initial tightening: 37 ftlb. → Final tightening: 90
9. Connect front cardan shaft to transfer box. → Initial tightening: 22 ftlb. → Final tightening: 90 °
Last edited by e30rapidic; 04-09-2018 at 09:48 PM.
Went digging on AllDataDIY - they have torque values for mounting a transfer case to the vehicle, but no data on rebuilding one (natch since the dealer mechanics treat it as a sealed unit.. remove/replace - no repairs). Here is the data I glommed from AllData:
No more “pulsation” or “stuttering” fluid fixed it
Originally Posted by deilenberger
Since you're the guy getting it done, and in touch with the dealer - think you could ask for a few more details about it? I tried Google - and it came up with nothing based on my searches. I'm sure it's out there somewhere.. but where?
woohoo
I had a pulsation get worse over a week, a drastic stutter, in acceleration, no CEL, no codes, my dealer Pfaff Porsche in Vaughan Ontario, Canada, quickly, and free (I can smooth talk anyone) added the “ford friction modifier” and it completely eliminated the stutter.
Hope me that helps anyone with issues diagnosising a transfer case issue.
I cannot believe how how smooth it is now.
Thank F’ing god, transfer case is $5000-7000 depending on who you ask (Canadian dollars)
Well said. I’ve never purchased an extended warranty and won’t start now. When my warranty nears expiry, I’ll either self insure if I am convinced it will be reliable or go back to my other brands. I just hope my transfer case goes soon so I can keep it. I’m not really worried about other things on a base.
woohoo
I had a pulsation get worse over a week, a drastic stutter, in acceleration, no CEL, no codes, my dealer Pfaff Porsche in Vaughan Ontario, Canada, quickly, and free (I can smooth talk anyone) added the “ford friction modifier” and it completely eliminated the stutter.
Hope me that helps anyone with issues diagnosising a transfer case issue.
I cannot believe how how smooth it is now.
Thank F’ing god, transfer case is $5000-7000 depending on who you ask (Canadian dollars)
Do you think you can smooth talk the dealer into giving you the PN of the "Ford Friction Modifier"? They make a few types and googling it comes up with multitudes of possibilities. Tell him it's for your poor widowed grandmother who lives in Argentina or something..
And I can see how that might help if the clutch plates in the case start getting sticky - just like with a limited slip differential (which is what the friction modifier is made for..)
03-25-2018, 01:10 PM
