np231 skips past 4-Hi

I have been collecting NP231 parts for a while and have managed to put together a full unit from the pieces. No idea what I'm going to do with it. Anyway... it works correctly except it skips over 4-Hi without stopping. If I tease the lever into position, it works fine, but it jumps out of position if it gets bumped at all. I thought for sure it was some kind of problem with the detent wheel and swapped it with another but same damn thing happens. Thinking I might drill out the detent notch a little.

Anybody run into this before?

There are two different size detents and detent springs. Maybe you're using the wrong size in the wrong case??

This is what the shift selector looks like, there's not really a way for it to skip 4Hi

I might be using a 242 detent cap and spring. I was going to check that actually, didn't know they were different.