What a beauty! It's a complete echo to everyone else, but I cannot imagine this is anything except a 3600 (3/4 ton). Pretty certainly it's not a 3100 unless someone has done some very strange swapping of parts.
The bed looks short from the picture, and because of spare, but that looks identical at a second look to my wheelbase and the bed length (7' bed and 125" wheelbase)
The front of the 3/4 ton diff is more of a 'normal' straight input type instead of the very off-set input of the 3100.
Also yours likely has a 2 piece driveshaft (3/4 ton).
lastly grab a tape measure and check the wheelbase, probably likely that it's about 125 1/4" (3/4 ton)
Last edited by 49ratty; 03/03/2019 11:11 PM.
