I'd do the following:
1. Check fluid level
2. Replace TSS (Turbine speed sensor) see transaxle forum for how-to's.
3. Replace manual shift position sensor on top of tranny.
4. Check wiring going to atx, is the insulation falling off and are the wires bare? If so you will need a new harness.
5. Replace ECT sensor (engine coolant temp) not the one for the dash gauge - it affects atx shifting
If you still have problems after the above then I would suspect solonoid shift pack.
Bob
