4-speed tail shaft

I'm going to have to check but here's what I remember.........

When I put the Advance Adapters shaft in my old Landcruiser, I wanted to use a 3.xx low gear and their shaft would not fit a 3.00 low gear because the main shaft was smaller? in a 3.xx low gear?

Or am I confused and thinking only of a OD box?

By the way, those Advance Adapters shafts were real POS too bad I didn't know it at the time

(A833 to Jeep transfer case) Too much shaft end play tears up the 3rd gear, and the shafts are soft, wears out on the Jeep drive gear end.