Unofficialbmw.com

LAHKNUT

Been having a problem with our 740i when shifting from park to drive. When selecting drive the transmission does not seem to fully engage and the car feels as if it being held in place by a tractor and only creeps forward slowly regardless of engine RPM. Then after depressing and holding down the accelerator the car "breaks loose" and surges suddenly forward.
A second symptom that has developed is that at times when shifting from any gear into neutral the car will actually backup as if it is in reverse. Yesterday for the first time when placing the car into park and releasing the brake the car was in reverse.
A third symptom: On occasion through this we have had a sudden metallic grinding noise occur when the transmission was shifting to or from any gear position.
Has anyone heard of this problem/condition? We have a rebuilt transmission and it has been to a dealer for a diagnostic and passed with no problems.
They did not have any suggestions for us so they replaced the ignition key barrel, this was on the idea that it might be sticking but that has not helped.

Power1 · Joined: 25 Jan 2002 Posts: 2 Location: Los Angeles, CA

I had a similar problem with my 94 740il, although possibly not quite as severe as you describe--but all similar symptoms.

The car was still under warranty (100K mi extended warranty) so BMW rebuilt half the transmission. This apparently was a big deal that required a transmission "specialist" that the dealer brought in to the job...and it took the better part of a week.

I had the same issue with the car actually going into reverse when in neutral, but did not even realize it--the dealer informed me that was happening. They all seemed astonished at the problem and that I could even continue to drive the car.

The lack of power when initially putting the vehicle in drive was particularly noticeable when attempting to accelerate from a standing stop going up hill--there was barely enough power to get the car moving--it felt roughly equivalent to trying to start out in 2nd gear instead of 1st.

Anyhow, the fix was a substantial transmission rebuild. Haven't had any problem with it since.