Mechanics

SHIFTING PROBLEMS

2001 BMW 740

Transmission problem
2001 BMW 740 V8 Two Wheel Drive Automatic 93000 miles

I have purchased this car 3 months ago and after driving for 1-1.5 hours, the transmission will downshift into 4th gear. Usually after a while, it will get back into 5th gear. No error codes are found. The car drives great with this exception. Can you advise me on what to do?
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6787737765
August 24, 2009.



Pendulum shifting can be caused by several factors, software, poor TCC lockup and/or a bad torque converter, intermittent or plausibility issues within the speed sensors inside the transmission. The transmission should be interrogated with the BMW software at the dealer level and then perhaps a path of repair could be determined. If I had to guess, I would say Torque converter, it sounds like it is shifting into torque converter clutch lockup and the clutch is failing to lock up and replacement of the converter may be in order. Typically a repair facility will charge a diagnostic fee for this information.

Dr. Hagerty
Aug 25, 2009.