Two problems related to transmission failure have been reported for the 2004 BMW 745.
Loss of acceleration while driving the car. Happens when you accelerate quickly specially while changing the lane. When this happens, the instrument panel goes dark, then I need to pull over shut the car and restart. When the mechanic diagnosed it, based on the dtc code, he first recommended changing the battery, which I did. The problem remained the same, and based on the dtc code changed the alternator. And the problem is still there. BMW refuses to pay for the repair, they say that this can happen due to the age of the car. I don't expect that a BMW transmission should go bad under 73k miles, even if the car is 10+ years old. The car has never been driven in snow/ice, stays in garage from oct - April. It's unfortunate that BMW refuses to assist with. Have been reading various forums that a lot of people having this issue when the transmission failsafe message comes. I would like BMW to step up and take the ownership of getting this issue fixed.
Numerous warning lights including "possible transmission failure" and "loss of stability control" lit up on my 2004 BMW 745li. The vehicle lost its ability to accelerate, which extremely dangerous in the high traffic situation I was exepriencing on the highway. This failure is in additon to numerous warning indicator lights that appear intermiitenly in the vehcile and then reset themselves once the vehicle is truned off and restarted. The diagnosis by BMW was that the mechatronic unit on the transmission had failed (after only 70,000 miles, this is barely the break in period for these vehicles). The total repari cost was quoted at $5,000. The machatronics unit was replaced and seems to be working for now. Upon reading up on issues related to the BMW 745li it is amazing that no major recall has been initiated on its electricals, transmission, and computerized control systems. All of these seem like huge saftey concerns as the vehicle tends to fail while in traffic.