2001 BMW 750Li Delayed Shifting

2001 BMW 750LI
115,000 MILES • V12 • 2WD • AUTOMATIC
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DONALDLEW
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Car has ZF A5S560Z transmission, GS 9.22.1 tranmission software with M73TU motor.
After stop and go driving, shift points increase to 40 mph, 60 mph and 75 mph with no 5th gear.
Could there be a signal problem with the DME? Seems the TCM is going into adaptive program that delays upshifting because of either aggressive driving or hill climb or hill descending mode. Front tires OK.
Shifting returns to normal after engine is shut down for at least 15 minutes.
Trans oil service before and after shows clean pan and screen and fluid which is clear and not burned. No trans fault codes using Peake OBD II reader. Replaced TCM with a TCM from another 750iL, same delayed shift problem after stop and go or closed throttle hill descent.
Jul 10, 2009 at 7:35 PM
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DOCHAGERTY
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It could be that there is a plausibility issue between the input speed sensor and the output speed sensor. It could also be a software issue, has BMW been involved?
Jul 11, 2009 at 9:14 AM
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DONALDLEW
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The dealer has not been involved because I have little confidence in them. I am at Concord, California.
Jul 11, 2009 at 10:18 PM
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DOCHAGERTY
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Weatherford or East Bay are possibilities too.
Jul 12, 2009 at 12:02 AM
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DONALDLEW
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Your suggestion of speed sensors or software goes beyond what we can do. Unfortunately, the dealers service departments have priced themselves out of the market.
Jul 12, 2009 at 4:53 PM
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DOCHAGERTY
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An E-38 750 that has issues and wont go to the dealer because the dealer has priced themselves out of the market says something about the condition of the field of car repair, doesn't it. There are independents out there in the bay area, many could assist you.
Jul 15, 2009 at 8:12 AM