first off i have a np231 t/c. can anyone tell me what this is that is circled.

 

That screw holds a spring and a plunger in place for the shifter positions. There is also a seal (that you need to replace from what i see). Do you want the PNs?... of course you want them...
screw:5300 8216
seal: 8350 3128
spring: 5300 8218
plunger: 5300 8217

 

That's what I needed to know. Because yes it is leaking, it's the only leak on the whole truck and it's one of the most important piece of equiptment, to me anyways.

 

A common oil pan plug copper seal should be fine if you don't want to go to the stealer, but you will need to drain the TC fluid...