The chassis is pretty much J-truck stuff. It was altered just enough that it’s not fully interchangeable, but a lot of J-truck hardware mounts right up. The higher GVW trucks like this had a 4.10-geared semi-float Dana 60, with an optional Trac-Lok. Lower GVW trucks had a semi-float Dana 44. A set of 4.88 cogs were optional in both axles.