In January 1977, together with other six U.S. companies the AM General took a part in a competition to create heavy vehicles for army with a total weight of 23-34 tons. In June 1977, the company won this competition, presented the cheapest car.
The chassis for these trucks was taken from Centaur crane trucks of CCC company. Trucks were equipped with a 6-cylinder Cummins NTC400 (14,0 l, 400 hp) diesel engine, semi-automatic 16-speed transmission Caterpillar, one-stage transfer box Oshkosh with a pneumatic actuator, rear axles Hendrickson and 20 or 22 inches tires. By the end of 1984, 7,3 thousand trucks of this models were produced.
Range included the following models:
- M915 – 14-ton 6×4 tractor with a Cummins NTC-400 engine and transmission Caterpillar.
- M915A1 – version of M915 with a Cummins Big Cam II engine and automatic transmission Allison. Production was started in January 1983.
- M916 – 14-ton 6×6 tractor with a Cummins NTC-400 engine and transmission Caterpillar.
- M917 – 20-ton dump truck.
- M918 – distributor of bitumen on the M916 chassis.
- M919 – 20-ton chassis for mixers 8×6.
- M920 – 20-ton tractor 8×6. It was used together with heavy trailers – 25-ton M172A1, or 40-ton M870.
In 1990, new updated models M915A2, M916A1 and M917A1 (manufactured by Freightliner) replaced M915, M916 and M917.