BMW Repair: 1997 E39 gears shifting problems, high mileage, sensor error

Question
A week ago, my car started stalling before it would pick up. The speed sensor error code came on after a read out. Also the car was doing over 4000 rpm to get to 60mph.
After replacing the life time fluid, the shifting got better at higher speeds, but was still slipping on lower speeds. My repair shop now suggests I replace the Torque Converter solenoid. I was just wondering if you have seen such a case before and have any suggestions.

Answer
Vince, there is a service bulletin on this issue         SIB 24 01 00 if the conditions and fault codes apply to this situation. You can get a copy from the dealer if you wish. It is better than replacing the trans. if it works. If The trans. has high mileage I would replace it.
-Evan