Where is the plug to fill the transfer case?

I can't find it, too much grease and stuff all over. Where on the transfer case is it located, what side? Its a 91.

Also does it just use ATF? I didn't get an owners manual with mine. :(

Thanks!

From what I can see the plug requires the end of a 3/8th socket extension, but there is no way I can apply enough force to unscrew it before the socket end slips out. How the heck to do you get the plug out?

From what I can see the plug requires the end of a 3/8th socket extension, but there is no way I can apply enough force to unscrew it before the socket end slips out. How the heck to do you get the plug out?
Try tightening it first to "break it free" It will make a distinct pop. Then it will be loose enough to undo. This trick works on all things considered fasteners by rotation so remember it.