First off this is an excellent forum for Gen III GM V8 equipped vehicles.
Truck is a 01 Suburban 5.3 4WD LT Autoride
Yesterday I started doing some of my 100K maintenance work and got around to the transfer case and noticed it has a large allen plug for the fill. Naturally I didn't have that size and was wondering what size it is so I can get a wrench that fits it.
Also does the 5.3 have the block drains for the coolant like earlier model small block engines.

OOPS Just realized I posted it in the performance section instead of the general section