Hello crconsulting,
early .6 AT really had a problem with the F2 Free wheel unit- in particular in Mod 163. The symptoms match. The F2 is renewed along with the sungear assy. and the job is (once you have the AT on the stand) rather an easy one.
However, I must say that before you go into that job, replace the so called "electric kit" on top of the valve body. It's the black plastic frame holding the solenoids. Early ones had non insulated circuit boards and loved to shorten out by metallic debris and dust. Symptoms then were similar.
Have the DTC read out in any event!
All the best,
Dokta