B13 A/T transmission RL4F03A

[B13_Red]

Observations:
* Overdrive slips back to third gear when accelerator is touched; started when temp's reached freezing for a low. O/D stays in its 4th gear when coasting
* 2nd gear has been shot for at least 5Kmi, and I've located the valve body spring fix for that one
* 138Kmi and original transmission, no transmission work has been done

Done:
* Changed transmission oil before the O/D problem; checked/snugged valve body bolts.

Thinking one of or multiple transmission filter, valve body spring kit, TCC solenoid, or O/D solenoid... Any thoughts or suggestions? Thanks.

[B13_Red]

Other Observations:
* TCC solenoid powers (12V) when the car starts, and stays powered through all speeds. Voltage check at the terminal block on PIN going to the ECM. Looks like the ECM closes the 0V leg in the TCC circuit to energize at engine start- that doesn't seem normal.
* O/D Cancel switch works- drops to gear# 3 when O/D is OFF
* TCC solenoid resistance is 27 ohm