In 1978, AM General manufactured and delivered a set of heavy duty trucks to the U.S. Army known as M915 series. The M915 series provide heavy vehicles in the 20 to 34 tons range, which complements the M35 2.5 ton and the 5 ton M809 and M939 trucks. The M915 became a baseline model for the series, which includes the M916 Light Equipment Transporter (LET), M917 Dump Truck, M918 Bituminous Distributor, M919 Concrete Mixer and M920 Tractor.
The chassis for these trucks were taken from Centaur commercial trucks of CCC ( Crane Carrier Company ). There are 3 basic chassis for the series; 6x4, 6x6, 6x8. The M915 Line Haul Tractor (LHT) uses the 6x4 chassis with a primary function to move containers of cargo long distances on hard surface roads. The M916 LET uses the 6x6 chassis for road and cross country transportation. The M917 20-ton Dump Truck uses the 8x6 chassis with a 12 cu yd dump body. The M918 Bituminous Distributor uses the 6x6 chassis for road and airfield construction. The M919 Concrete Mixer uses the 8x6 chassis for construction work. The M920 Tractor uses 8x6 chassis for off-road use.
The M915 uses a 400hp Cummins NTC 400 turbocharged diesel engine with a Caterpillar semi-automatic gearbox with 16 forward and 2 reverse gears. The M915A1 uses a Cummins Big Cam II engine with an Allison 5-speed automatic transmission. The M915A2 uses a 400hp Detroit Diesel DDE 12.7-liter. The M915A3 uses a 430hp Detroit Diesel 60 DDEC IV 12.7-liter with an Allison 6-speed automatic transmission. The M915A4 “Glider Kit” program was started and involves removing the engine, rear axle/suspension assembly and pintle from a donor M915 and installing onto a glider (truck without a drivetrain and rear axle/suspension assembly). The M915A4 “Glider Kit” consists of; an air conditioned cab, wheels and tires, muffler, radiator, fifth wheel, Allison automatic transmission and front-rear axle hubs with ABS. The M915A5 upgrade is a 500hp engine, dual fuel tanks, integrated armor, and added interior cab space. These have replaced the older M915, A1, A2 and A3 models. The LMTV, MTV, and HEMTT Families are the modernized replacements for the M800 and M900 series trucks.The M915 Line-Haul Tractor is used with trailers:
- M871 Semi-Trailer (Flatbed, 22.5 Tons)
- M872 Semi-Trailer (Flatbed, 34 Tons)
- M1062 Semi-Trailer (Tanker, 7500 Gallons)