Car Will Only Shift Into First Gear - 1999 2.3L Auto

STL Accord

New Member
Jun 4, 2020
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St. Peters, MO
I just finished up an engine rebuild on the F23a1 in my '99 LX sedan with auto (BAXA) transmission. Everything is reinstalled and working just fine, except for the transmission. Whether I put the shifter into D4, D3, 2, or 1, the transmission will not leave first gear. It will continue to just rev and the transmission does not even attempt to shift (no clunk, slip, etc). Reverse also does not engage - same thing, you cannot even hear the transmission attempt to engage. Reverse is essentially behaving as neutral.

I have so far ruled out:
  1. Linkage and Neutral Safety Switch - the dash light and my shifter position match up correctly each time. Park, neutral, and first work as they should where they should.
  2. Shift solenoids and pressure switch - I have confirmed the resistance across the solenoids is within spec and have even made them click using battery voltage.
  3. Grounding - I am able to actuate the solenoids using the engine/tranny as ground.
  4. Wiring Harness - I have triple checked that all pigtails are on the correct solenoids/sensors. I am entirely confident this is correct.
I am thinking this must be something in the transmission control system? This is internal to the PCM/ECU on these, correct? Signs are beginning to point to fried clutches, but the tranny worked fine before the swap, and it is not slipping, banging, or even attempting to shift into any gear except first.

Does anyone have any recommendations of what I could try next? I know a dealer will not give even have the effort I have to diagnose thus far, and ultimately their answer will be to replace it. I am not convinced the issue is internal to the transmission however.