In the mid 1950s Autocar offered rugged "pit fenders" for their on-off road contractor's trucks. You'll also notice the belly pan guard to protect the engine. Toward the end of the 1950s a more efficient higher capacity radiator was an option. This was mounted outside outside the sheet metal and is generally referred to as a "hard nose" either on Autocars or Macks

The body here is a Marion 13 foot long 12 yard capacity part number 26288, the truck is number 95130.

This is a modified kit 95046 60 ton trailer, the third axle has been removed as was very typical for the late 50s and 1960s. It is being pulled by a C-100 Autocar, a large tractor for the late 1940s.

Here’s an Autocar 2036, an off highway setup. It has a Sheepscot 20 ton rock body part #26293 one piece urethane casting. This would have been a new truck in 1954 when Autocar introduced the pit fenders as a factory option.

The right side view shows the connection for an exhaust heated body to keep the material from freezing in the winter. In the box there’s a flapper valve that directs the engine exhaust down when the body is raised.
The wheelbase is 198”, tires 12.00-24. s/n 101368