Section II. DESCRIPTION
The 5-ton, 6x6, M39 series trucks are designed for use over all types of
roads, highways, and cross-country terrain, in all types of weather. They will ford hard
bottom water crossings to a depth of 30 inches. Thevehicles are powered by a gasoline, diesel
or multifuel engine and are discussed separately, where necessary, throughout the manual.
All are equipped with a manually operated, five-speed transmission and a two-speed transfer
case which transmits power to the front and rear axles. Service brakes are of the air-actuated,
hydraulic type. The cab is enclosed with removable canvas tarps. All vehicles are equipped
with a spare wheel and tire, and a pintle hook at the rear for towing a trailer.
This vehicle has been designed to operate safely and efficiently within the limits
specified in this TM. Operation beyond these limits is prohibited IAW AR 70-1
without written approval from the Commander, U.S. Army Tank-Automotivc Com-
mand, ATTN: AMSTA-CM-S, Warren, MI 48397-5000.
1-6. Differences Between Models.
a. General. The 5-ton, 6x6, trucks covered in this manual are of various wheelbases. body
styles and engine types.
b. Dump Truck, M51 Series. The M51 dump truck has a 167-inch wheelbase, 11:00 x 20
tires and dual rear wheels. A 5-cubic yard capacity dump body and twin-cylinder hoist assembly
is mounted on the rear of the chassis.
c. Tractor Truck, M52 Series. The M52 tractor truck has a 167-inch wheelbase, 11:00 x 20
tires and dual rear wheels. A fifth wheel assembly, approach plates, and deck plate, suitable for
hauling trailers, are mounted on the rear of the chassis. Tractor-to-trailer brake hoses and
connections are mounted behind the Lab.
d. Gargo Truck, M54 Series. The M54 cargo truck has a 179-inch wheelbase, 11:00x 20
tires and dual rear wheels. A 14-foot flatbed cargo body is mounted on the rear.
e. Dropside Cargo Truck, M544A1C and M54A2C. The M54A1C trucks have a
179-inch wheelbase, 11 :00 x 20 tires, and dual rear wheels. A 14-foot flatbed cargo body is
mounted on the rear. TO permit side loading, the cargo sides are hinged along lines where
sides and cargo bed join.
f Cargo Truck, M55 Series. The M55 cargo truck has a 215-inch wheelbase with 11:00x 20
tires and dual rear wheels. A 20-foot cargo body is mounted on the rear.
g. Tractor Wrecker Truck, M246 Series. The M246 tractor wrecker truck has a 215-inch
wheelbase, 12:00 x 20 tires, and dual rear wheels. A hydraulic crane and fifth wheel assembly
are mounted on the rear of the chassis.