Rear axle shaft compatibility - fine spline

[Jacket]

I'm looking at picking up a spare rear axle shaft for my 1976 FJ40, and in looking at the SOR reference material, it says that there is a difference between 9/73 and 1984 rear axle shafts versus 1968 - 9/73. SOR says the early model has a removable race, where as the later axles do not.

No idea what is meant by this? Can I run a pre-1974 rear axle in my 76, or is there some wheel bearing and race differences that would force me into only a 1974+ axle?

 

[71-CRUISER]

You can run either as long as they are both fine spline where they go into the diff. There is no significant difference especially since you cant get replacement collars any more.