I tried to remove the upper fill cap on the transfer case and it looks like I need a 1 1/8 SOCKET to do it because it is recessed- I can't get my channellock or crescent wrench to grip. Can anyone confirm this nut is a 1 1/8 before I go out and buy a new one? (or can it be metric?) (I have a '96 GMC Jimmy, 4wd, 4.3 Vortek)

 

They typically have a 10mm internal hex, but there are some that have a 30mm external hex plug. 1-1/8" may or may not work.

 

Thank you! 30mm will be my answer!