Any advice is much appreciated. I have a 1989 740 gl auto. This car used to fly me to Mexico and back at around an average 80mph. But now it wont upshift too OD. Button on shifter works the arrow on dash. Help!!
it most likely is the relay,that is the cheapest fix.but with this model car and its age it could be the solenoid on the drivers side of the trans.It has one wire going to it,have someone work the switch while you check it for power at the solenoid,if it has power you should be able to feel it click.In other cases if the solenoid works the trans will need replaced,or rebuilt if you can find some one who can do it.