*Transmission Fault* Clutch, ISM, Alt, Batt?? [Archive] - Bimmerfest - BMW Forums

: *Transmission Fault* Clutch, ISM, Alt, Batt??

06-19-2012, 11:47 PM
This is my first thread and I've been researching a while for "transmission fault" and found: "Integrated supply module", Alternator, Battery, sleeve + adapter + oil.
Here are the tranny symptoms for my 2006 750Li.
Took the car to the Indy on Thursday (6/14/2012) for: Oil change, coolant flush and replaced the "Flex Disc" (that connects the shaft to the tranny trying to solve a mild thump when shifting in low gear). The car drove great for the next 2 days and on Saturday evening, feeling good about how things were turning out, I decided to take it to the detail shop for a complete cleaning service (compound, wax, shampoo and......... ENGINE CLEAN). Right after I drove off the detail shop, the tranny started acting up.... within the first 1/4 of a mile, the tranny was slamming hard (like being rear ended http://s1.bimmerfest.com/forums/images/smilies/iono.gif) then, started loosing acceleration and finally the "Transmission Fault. Possible reduced acceleration" warning message showed up. Drove slowly until I found a place to safely park, turned the car off for about 1/2 hour and started it again. After re-start, the error message was gone and I drove about 3 miles and parked for two days until I had the time to go back to the Indy for a check up. On Tuesday 19th 2012, started the car normally with no error messages and started driving to the Indy after calling him with the tranny feedback (He mentioned that it could be a voltage problem). After 20 minutes of driving, the "Transmission Fault" message came up again right in the middle of the hwy at reduced speed. Barely made it to the shop (not before making a lot of drivers angry at my turtle) and once there, there was no reverse. Scanned the system and some codes came up (he took a picture of the codes. I didn't write them down, but he will share the picture if I ask. He didn't check voltages and when I asked why, he replied that the car was starting just fine). He brought a "transmission specialist" from the shop around the corner and the diagnostic was "you need a new/used tranny or rebuild". I replied that everything was fine until that engine wash, that maybe there was some wet plug somewhere. I was given the option of rebuild the tranny for $3,800 or try my luck by changing the oil, adapter and seal which I did. After the tranny service, the car moved again on all gears including reverse. Test drove for 3 miles with no problems, went back to the shop to pay and on my way home (just 4 blocks away from the shop), the tranny died/fail safe again. Left the car parked on the street, gave the key to the Indy and took a cab home to evaluate the situation. Anyone with the same symptoms?? I really, really don't have $3,800 to re-build and already spent $800.00 on oil changes, flex disc, coolant flush,seal, adapter.

Is it going into fail safe mode because:
A) Tranny gets hot after 20/30 minutes of operation and it shuts down?
B) The Alternator gets hot and loses power? (I was told about 3 months ago by another Indy that the alternator was bad but after the re-set the computer I haven't had any problems with the car until now)
C) The battery loses charge after 20/30 minutes?
D) Bad Integrated Supply Module (Maybe got wet during engine wash)?

Thanks for looking!