I’ve got a 93 w250 automatic transmission it has lost the tetent ball On the shift selector I know it’s mounted on the valve body I have a good gas valve body that the detent and everything works in My question is is a gas valve body in a diesel valve body the same thing or is there differences

 

I would replace it with one of these or similar, the ball only rides at the end of the boss and over time wear will allow it to fall out.
https://goerend.com/detent-bullet-spring/

 

Not quite interchangeable, there are some differences.

 

You need to upgrade the detent from a ball bearing style to a bullet style. Good time to do a shift kit.