Mine is a 3/4-ton (3604) and 4.63" is called out in the FAM, but
for what it's worth, I get right around 4" from the back side
of the front pocket to the front side of the first vertical
angle. My spare fits fine.

The call out for the 1/2-ton (3104) would be 2.88".

DG


Denny G
Sandwich, IL