Actually...they do in a kinda sorta way...
Why refer to my 8.6K GVWR Burb as a K3500...
Most all 8.6K GVWR Suburban's has the same rear axle as the 3/4 ton and 1 ton pickup (GMT400/800 and some later platforms)
Mine is rated by GM at 6,000 lb RGAWR. AAM is the supplier to GM and rates it at 10,000 lb GAWR, but GM installs the brakes and suspension system
This is the same rear axle on the 3/4 ton and 1 ton pickups. They have the wider shoes (why parts counter folks will ask how wide are your rear shoes when ordering stuff). The other difference is in the rear cylinder bore dia, MC bore dia and maybe some other parts/software.
Ordered mine with the F60 option. A $67.00 buck option for the 'Snow Plow' package, that begets 1 ton front torsion spring bars
When shopping, look at the glove box option label that lists all factory options it left the factory with. F60 is that snow plow option RPO code
