Oshkosh MK31

   The Oshkosh MK31 tractor truck is a member of Oshkosh MTVR family of military vehicles. It was designed to meet a US Navy Seabees requirement. Its production for the US Navy Seabees and US Marine Corps commenced in 2005. First production vehicles were fielded in 2006. In service the Mk.31 tractor truck is referred as Medium Equipment Transporter (MET). It has been deployed to Iraq and Afghanistan and proved itself well.

   This tractor truck is a purpose-designed heavy-duty military vehicle. It utilizes the same (but shorter) chassis, engine, drivetrain and running gear as the baseline MTVR Mk.23 cargo truck. It has a commercially-compatible fifth wheel. This tractor truck hauls semi-trailers with fuel, water, combat vehicles, construction equipment and a variety of other military cargo. It can haul loads with a maximum weight of about 30 000 kg. Vehicle has 70% on-road, 25% unimproved road and 5% off-road mission profile. This vehicle has expected service life of 22 years.

   The MTVR Mk.31 is an integral part of the US Navy and US Marine Corps logistical backbone. The US Navy vehicles are used in conjunction with a variety of commercially-based semi-trailers. The US Marine tractors are primarily used with M870 flatbed and M969 and M970 fuel tankers.

   Engine is located under a forward fiberglass bonnet. Roof of the cab with hinged aluminum windscreen and door frames can be folded down to reduce overall height. The Cab accommodates driver, co-driver and one passenger. For operation in combat zones cab can be fitted with add-on armor kit. It provides protection against small arms fire, artillery shell splinters. Furthermore armored cab withstands blasts equivalent to 6 kg of TNT. Also a roof-mounted 7.62 mm or 12.7 mm machine gun can be fitted.

   The Oshkosh MTVR Mk.31 is powered by the Caterpillar C-12 11.9-liter turbocharged diesel engine. Engine was uprated from 425 to 445 hp. It is mated to an Allison 7-speed automatic transmission. Vehicle has a full-time all-wheel drive. It also has an independent suspension and is fitted with a central tyre inflation system. Tyre pressure is adjusted from the drivers seat depending on terrain conditions and payload. Also it has an all-wheel steer. Some commercially available driveline components were used in order to reduce production and operating costs.

   With some preparation vehicle and trailer combination can be airlifted by the C-130 Hercules aircraft. It can be also airlifted by CH-53 helicopter.

Variants

   Oshkosh Wheeled Tanker, a version of the Mk.31 for United Kingdom. It is designed to tow specialized semi-trailers with fuel and water tanks over unimproved roads.