[QUOTE='74 UA FJ]So Poser, do you think it's just a fraction of the people that have orions that experience this problem?[/QUOTE]
There are people that have posted up they are having issues with the case, and others that have posted up that they are not. From what I have read out here, and the conversations with Randy at AA, I do not think that the majority of them in service are having issues. But, with that said, there are people that have built these that are not out here posting up their opinions, and I really do not feel that it would be a smart to assume that since we are not hearing anything out here, that there are not issues. This is a very large forum, but it is not the single source for information on the 40 series Land Cruiser, or the Orion transfer case.
There are many variables with these cases, and a very important one is who put it together, the parts used to assemble it that are not included with the Orion, and if they realized what was going on with them at the time of assembly. While it is similar to a Land Cruiser transfer case, there are little things about the assembly, that make them just different enough, and can increase the tendency for the case to come out of gear if not taken into consideration. These have been covered in previous threads, but I will list a couple below...
The free play of the high and low speed gear on the main shaft. If this is not limited, the gears could easily walk on the shaft and come in contact with the high/low speed shift collar.
Speaking of the shift collar, this needs to be a new piece, or at least, very lightly used. I have only used new ones on the cases that I have assembled. Something else that I have noticed was the difference in thickness of the shift collars found in different transfer cases, compared to a new piece. The new ones seem to .050” thinner than the older ones.
I have also only used new, or very lightly used main shafts for the assembly of the Orion. If the bushing area on the shaft where the high and low speed gears ride is worn, this will exaggerate the free play issue addressed in the first part of this list.
Another variable is the shift shaft, and its spatial relationship to the main shaft, shift fork and shift collar. There is a machining relief in the case for the retaining tab for this shaft. If this relief is cut deeper or shallower on some cases, this will position the detent locations for the shift fork on the shaft closer to the high-speed gear, or low-speed gear, depending on how deep it was cut. Something else with the shift shaft is when the bolt is tightened that retains the tab, holding the shift shaft in place, this could rotate the shaft, not allowing the ball to seat fully in the relief for it, and consequently, not having the same effect that the ball seating into the full relief would have. This would allow the ball to sit on the edge of the relief and not down in it, like it is supposed to, and keep the fork and shift collar in the selected position.
Something else that ran through my mind was if the high and low speed gears were made .125” thinner on the shift collar side, creating a larger cushion or gap between the shift collar and the gear that wants to bump it out of gear when it contacts the collar, in the event that they have another run of gears made to correct the dog teeth issue. I do not think that this is something that will happen however, and would not hold my breath.
If I have missed something, please post up, and I will add it to the list!
Thanks!
-Steve Cramer