additional series indications..
3700 is a 3/4 ton 'forward control chassis'
3900 is a 1 ton 'forward control chassis'
1.5 ton trucks are in the 4000 series, with the specific number based on the wheelbase
4100 1.5 ton 137 inch wheel base
4400 1.5 ton 161 inch wheel base
Two Ton trucks are in the 6000 series, again the specific number indicates the wheelbase.
The Cab Over or 'COE' trucks are in the 5000 series, and again, the specific number in the series indicates wheelbase.
