Gearbox software upgrade is something worth doing for sure.

But I did this 30 days ago and its still working for me. I will go get Engine and Gearbox Software updates soon though.

Use 30 secs reset method. It will solve the problem.
-Turn key to position 2. But dont start the engine.
-Floor the gas pedal for 30-40 secs.
-Release the gas pedal, step on brake and start the engine.
-Drive FORWARD (Not reverse, so make sure you are out of your garage before you attempt to do the transmission reset)


This is a temporary solution.

__________________
2001 4.4 x5 - owned since 2004.