Help!! 4KCSQ Center diff. oil swap!!

[Nicholas Menaker <72074.2716@CompuServe.COM>]

Well, I have  begun the transmission oil and center and rear diff oil swaps on
this 86 4KCSQ.  The rear diff was fine, the front transmission went smoothly,
but now the center diff. seems to be a real pain.  Where is the filler hole?  is
it on the right side as one looks up?  How do you get the screw out?  There is
NO room there?  Is there a special trick for this?  
The car is in the air till I figure it out.  
Wait, does the transmission hole fill the center diff.  That would make it
simple, but crazy
Thank you for responses  Time is of the essence.
Nick out