This sounds like you are describing the 2 rows of needles found in the main drive gear which is the gear that extends into the clutch disc.
This is normally the first gear removed from your trans but the needles still fall out.
It is the last gear installed and from the front with the ball bearing still mounted unless it were a close ratio gear set but that wouldn't be in an early truck.So!
1) Reinstall the tailshaft without the needles after removing the main drive gear.
2) using grease stack the large needles in the main drive first-then there should be a thick washer between the large needles and the small needles which are stacked in next.
3) If the needles still are wanting to fall out when the main drive is slipped in place, find a way to rest the trans with the tailshaft pointing straight up then gravity will not be working against you so hard.
4)sometimes one of the needles,usually a small one, is dislodged when the main drive is slipped in and will prevent the gear from going all the way home.If the main drive doesn't go in far enough for the bearing retaining ring to go easily up against the case-take it back down and start over-DO NOT try to pull the main drive home with the bolts in the collar.
5) note the drain hole in the front of the case and the matching channel in the release bearing/main drive gear collar-they must be lined up as this trans has no front seal.
If the 2-3 shifter fork is locked up it probably is the fault of the syncronizer which selects 2 and 3.
