I had some trouble with my CA18 spigot when i went to bolt the gearbox up to my new motor and realised it didn't have a spigot in there.. I went and bought a ca18 manual spigot bush from my local brake and clutch shop and when i got it back it looked like it was too big to fit..
I then realised that the new motor did have a spigot, but it wasn't a small brass one like i was expecting, it was a large steel one of about 35-40mm outside diameter and the inside diameter was just smaller than the outside diameter of the brass spigot i had bought. It was possibly the auto spigot?? i dont really know.. All i know is that it was a complete bit** to remove!
In the end i sacrificed my steering wheel puller and welded it to the spigot and finally it popped out and i was able to fit the little brass sucker in behind where the old spigot was located...
I dont know if its the same problem your encountering but i hope it helps,
Mark.
also, i was told its a good idea to soak the brass spigot bushes in motor oil for a good few hours or more before fitting them as they are porous and soak up the oil. It made fitting mine pretty easy anyway..

from what I was told Nissan used on the the one size but the one I got was a little too big so I just grinded off the outside slights and tapped it in, I made sure the spigot went on the input shaft of the box first.

All goo then

Damo

Are you sure its not just tight?

Mine looked like it would never go but it did.

Maybe a silly question, did you get the old auto one out?

I have a CA18DET it was auto so i have bought a spigot but the nissan dealer said there were two sizes so at $3 each i took them both, but niether fit one way to big one way to small they said these are the only two listed are auto and manuel cranks the same has anybody come along this problem? And what did they do? I have not heard of this problem before thats why i think something stupid is going on...

Im running a stumpy box to.

Thanks in advance.....