Please help with NP218 issue

Hey guys, and ladies. I am putting in my freshly rebuilt transmission and noticed a weeping leak in my transfer case. TM's have been searched and I still don't know that it is. There is a plastic or some type of non metallic substance in the hole. Appears that it's possibly threaded. It's in the spot that rubs against the band holding the fuel tank. The included image is from the TM and points to the suspected hole. Please any ino is appreciated.

Funny, I'm working on the same issue today.

Rubber plug, not threaded or even really retained by anything but friction. Tapped the hole 1/8 NPT and put in a flush plug. Hopefully stops it from weeping. This is on a np218, not sure if the np242 is the same.

I wonder if thats what I got going on now...It was a knuckle+ low when I changed fluid. Then it started the leak. There is evidence that it has been happening in the past.

This is very common, the rubber plug dries out....if the Tcase is out, pull the plug and fill the hole with some RTV and reinsert the plug.

DatGuyC was right. Upon further investigation it was a rubber plug without threads in the hole. Also thanks Retiredwarhorses, that's exactly what I did. Cleaned the hole and plug, generous dab of RTV and popped it back in. Thanks so much guys! This site is a wealth of valuable knowledge! !