T/C main drive gear nut

is there any difference in main drive gear nuts? what I am getting at is that there are two different style nuts for regular style d 18 t-cases: castle nuts that require cotter pins and self locking nuts that do not. does the ones that are self locking help with end-play of the tranny mainshaft? I would think there isn't much difference because O/Ds for both use the same O/D lock not on the shaft.
Does anyone know the size / threadcount of these nuts offhand?
Thanks

 

I know this has been discussed before, the thread count of the nut.
The castle nut and the self locking should be the same thread.
technically, there are no end play specs for a T90 main shaft...
there are for the thrust washers to cluster gear to case
I have seen shims on the mainshaft inside for attempts to prevent 2nd gear from popping out
gonna search for that nut info......

 

I can't tell you the sizes without checking, but I just rebuilt my Dana 18. I had two of them and I know for a fact that they are not the same size. The one with the castle nut is larger.

I had the locknuts and they would fit one shaft and not the other. Much to my dismay it was the one installed in the case that it would not fit. I didn't know until after the case was assembled that the new nut wouldn't fit. I searched high and low for locknuts and castle nuts locally with no success. I even went to a supply house that "specialized" in fasteners. The guy looked at me like I wanted parts for the space shuttle. I finally took the larger shaft out and installed the smaller one so I could use the locknut.

Later I ordered a castle nut from Krage for the other shaft to have as a spare. I didn't want to go thru the looking for a nut that size and thread again.

I am sure one of the great gurus of Jeep will know both sizes and thread pitch.

JC