Missing 3rd on 904 trans
If you pull the VB looking for sticky shift valves, do an air test.
As for my understanding;
I fail to see how a stock 904 can start in any gear except first.... unless
1) the 1-2 shift valve is stuck, which could easily cause the slow 2-3 shift. or
2) the governor is stuck. But if this is the case, then the trans should always shift at the same roadspeed only slightly affected by the KD adjustment/throttle-position.
3) even if the L/R band fails to engage, the sprag will still put you in first, no matter which forward gear has been selected.
4) but if reverse works normally, then BOTH the L/R band and the sprag, and the Hi-drum, are all working normally
It's gonna be interesting, that's for sure.