Look at the front axle, if the hub caps/dust covers are pressed in like normal ones on small vehicles then it is a 1.5 ton, if they are held on with 5 little bolts/screws then it is a 2 ton.

Look at the the rear axle, if it is a 2 speed chances are it is a 2 ton, but not always.

Also the door tag says about 16,000 lb for a 2 ton and about 14,000 lb for a 1.5 ton.

Wheelbase of 137" is model 4100 or 6100.
Wheelbase of 161" is model 4400 or 6400.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
---All pictures---
"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-