Abrupt and Random Upshifting and Downshifting - 1994

After a few hours on the road my 94 SC experiences the auto tranny issue as described in the thread heading. It starts out very slow - goes from OD back to 3rd, then immediately back into OD. It will do this for a while, maybe repeating every 2 or 3 minutes. Then the shifting gets more abrupt, and may even downshift into 2nd for a split second. I had this problem a year ago and my trusted local shop was never able to duplicate the problem, and then I wasn't either. It just went away. But a long weekend drive and it's back.

If I shut off the motor and restart, the problem stops, leading me to think it's electrical. Clean fluid, regular maintenance, 34k actual miles, no other tranny problems. Any thoughts?

A bad MLPS or manual lever position sensor can give you these problems. The 94-95s had problems with the original sensor, has it ever been replaced or updated?

Joe

The MLP sensor is likely original. Not familiar with this sensor - tranny mounted? Something I can replace myself?

It's mounted on the side of the transmission. I've never changed one myself but it doesn't sound too difficult. A few screws and unplug the sensor, pretty sure it needs to be lined up properly.

Joe