Missing 3rd on 904 trans
Let me recap;
the trans passed the air-test.
the VB was cleaned.
the shifter is synchronized.
Reverse works.
Neutral works.
Second works
and Drive seems to work.
AFAIK, it is impossible for a 904 to start in Second........ unless
1) the 1-2 shift valve is stuck in the bottom of it's bore.... or
2) the 1-2 shift spring is missing, calibrated wrong, or installed wrong. It goes in FIRST, not between........., or
3) throttle pressure is lower than governor pressure, or
4) if line pressure has been re-routed to the governor circuit.