Look in TM 9-2320-361-34 chapter 12 page 12-1, that shows the steering shaft assembly. Page 12-7 shows the breakdown on the gearbox. Also you can see a complete breakdown in TM 9-2320-361-34P, Figure 115.
On Page 12-9 in the -34 part #5 there are two studs on bearings that slide in the channel on the gear #13. If the outer most stud is not on the gear do to a miss alignment then the shaft will not seat properly. You also have two bearings number 25 on each side of the gear that helps with the turning of the shaft. the ball bearings are in a circle and if one are more come out it will be impossible to re-seat the gear back into the box.
Also the shims that go between the tube and the box are there to set the pre-loading so steering play is at a minimum #23 at least 1 is needed but a kit will give you 10 If I remember correctly each one is .002" sandwiched between #22 gaskets. The gaskets are almost impossible to find I had to make a set.
Hope this was helpful but looks to be one of two things, if its just a misalignment issue it will be a pain but can be done in place. If its the ball bearings out of place than the only way to fix that is on a bench.