2005 4.8is transmission shifting / slipping issue

[desertfire]

Ok, an update on the action items for this thread...

I am just now getting back to dealing with this issue after being out of town for several weeks dealing with work... couldn't wait to get into this and figure it out.

I followed the posts that Propeller offered up (kudos Propeller, extremely informative and of awesome help!) and proceeded to execute part 1 of the fix: replacement of the mechatronic "adapter" seals. I replaced the square one as well as the 4 "cylindrical ones. I followed the procedure for draining and opening the transmission and removing the valve body. I wiped down the valve body to remove the black metallic "buildup" that was all over it.. not chunks or shavings, just thick black grime that was a little of everywhere. I'm guessing this is to be expected at 180k miles...

The old main adapter seal for the mechatronic was hardened and the gaskets shriveled. The cylindrical ones were actually shrunk to the point that they had receded into the main transmission body and were no longer even close to making contact with the valve body.

I would upload pictures but am not aware of where is a good place to upload them to where I could grant access to them for this web posting. I'll figure it out at some point...

After replacing the seals and refilling the transmission, the shifting is working far better and is definitely making a huge difference in a large part of the performance.

However,

The "slipping from 4th to 5th is still happening, however, the behavior has become consistent, and the metal whirring sound when the slipping occurs is no longer present, or at least it is not audible. I also learned today that his is called "shift flaring".

The pattern that I can tell is this:

· Drive Mode
o When accelerating at very low throttle, the gears drop fast almost to the point of choking the engine.
o With moderate throttle, the vehicle accelerates through the gears and if the tachometer is right around 2500 rpm, the flaring will occur, consistently.
o With a little more aggressive throttle, pushing the tach to ~3000 rpm the shift issue does not occur, but there is a moment of hesitation
o Going uphill causes the issue to appear more, but I assume that this is caused by needing a little more throttle which causes the system to fail when riding at ~2.5k RPM.
· Sport Mode
o When accelerating at moderate throttle it appears to not happen at a set speed.
o Going uphill apparently causes a hesitation in the shifting between 4th and 5th.
o One time the flare occurred when shifting from 4th to 5th under a little more aggressive acceleration
· Manual Mode
o No issues to report
o The shifting is crisp, very paddle shift speed… makes me want to get a paddle shift steering wheel.
o All gears are held effectively.
o There is a moderate “lurch” forward when the transmission is shifted manually from 2 to 1.

I reached out to the before mentioned “contact” of mine and he gave me the contact info for a ZF transmission “specialist” in San Diego. In speaking with the ZF guru, the contact there basically is saying that at 180K miles repairing the issue may just resolve into something else appearing that may need to be fixed, which may be costly. Also, they don’t repair transmissions, they only overhaul them, so this would basically turn into a transmission rebuild.

Looking at the schematics of the system, from secondary links in one of the posts on Propeller’s forum posting that he linked here, it appears that the only mechanical part in the system that could be causing this level of intermittent behavior would be a failure in the mechatronic valve body since it governs the shift points with the TCM system.

Tomorrow I will be reaching out to My Indie shop contact to verify the firmware on the transmission.

In the meantime, given the updates on the vehicle, does anyone have any idea where to dig on this problem? It is perplexing….

Your feedback is appreciated!