CalG

To any still interested:
Last night I read through a piece of technical literature from R. Bosch entitled "Electronic Transmission Control ETC" 2004 edition, 114 pages.

A very informative read! If we could have this calibur of information for our specific application, we would have NO Questions about the characteristics of the A8 autobox.
Some "bits" that I have checked as significant in the reading.

Learned "system pressure correction" is stored in non volatile memory. The learned value is termed an "adaptation" and may be some undocumented "hidden setting" yet to be discovered. The purpose of the adaptation is to accomodate unique transmission characteristics at each shift, and is limited to about 10% variation. No mention of any additional range. Again it would be a boon to have model specific information.

There are 5 basic "driver-types" ranging from Extreme Economy to XX Sport. No mention of what "coding" might do to the set ranges, perhaps block the extremes. "Driver- type" counts the number or value of events such as wheel speed kickdown frequency, lateral and linear acceleration. hill recognition, etc. over a time interval, sums these events and applies a shift profile based on the value (0-255)

The TCC recieved little mention, but there is a statement of "the controled torque converter lockup clutch (CTCC) sets a very low level of slip (40..50 rpm) and thus is an almost stationary state" This must then be the design performance criteria. The rub!

The PWM valves are driven near the 50htz range.

TCU's since 1996 using the 683xx processor have 256k Flash memory and 8k RAM. (There is hope to REFLASH these TCU's?)
2001 and newer MPC555 chips have more memory.

I must reread the entire document. I am sure there are many more bits of information that will be of interest.

Now I will inquire if there is such a piece of literature for our TCU's.

This Literature is available from Bosch quite reasonably priced. ISBN-3-934584-79-9 order number 1 987 722 127

Regards

CalG

audilvr

Maybe with your technical prowess (no kidding-- you are the most likely candidate to actually get a ZF engineer who knows something to actually tell you what the deal is with the A8 transmission issues.

I solved my troubles with a rebuild, but I should have been able to get another 20-30K miles out of the tranny.

CalG

I had thought to contact ZF NA, but put it aside. I am sure they have heard just about enough of this misery. They likely have no more a clue than you or I. Why? ZF produces the hardware, but Bosch (and Audi?) produce the controlling device and software. It's an "over the wall" syndrome. That is why I have pursued Independant service activities. The rebuilders a repair technicians have nothing to protect. If we truely crack this issue, I will personally return calls to all the contacts I have made to get the good word out.

Now, with that said. I have thought to contact Bosch with the module identity and try to obtain the design information there. I am quite sure that Audi has the component "tied up", but who knows. The current interest has expired on a 7 year old automobile. There are limits to secrets are there not?

Thank you for the prodding

Regards

CalG