The M809 series, known in military terms as the G908, was a family of heavy tactical trucks built for the United States Armed Forces. The basic cargo version carried a 5-ton, 14-foot load over all terrain and in all weather; on roads the load was doubled. AM General built every one of them between 1970 and 1982.
AM General M809 at a glance
| Maker | AM General |
|---|---|
| Military designation | G908 |
| Production | 1970–1982 |
| Class | 5-ton 6×6 heavy tactical truck |
| Payload | 5 tons (4,500 kg), 14 ft (4.3 m) load |
| Engine | Cummins NHC250, 855 cu in (14.0 L) naturally aspirated diesel |
| Output | 240 hp (180 kW) at 2,100 rpm, 685 lbf·ft (929 N·m) at 1,500 rpm |
| Transmission | Dana-Spicer 6453 five-speed manual |
| Transfer case | Rockwell-Standard two-speed |
| Wheelbases | 167 in (M810), 179 in (M809), 215 in (M811) |
| Tyres | 11.00×20, dual rear |
| Brakes | air over hydraulic, drums on all wheels |
Based on one source: the English Wikipedia article on the M809 series.
History of the AM General M809
An update of the M39
In the late 1960s the US Army needed more 5-ton 6×6 trucks, so AM General developed an updated version of the M39 series, which had been in service since 1951. The main differences were the engine and transmission. The hood and grille were lengthened to make room for the larger engine, and the lighting was updated to meet new US safety regulations. Every M809 has an air cleaner on the left fender, which is the quickest way to tell it from an M39.
Built by AM General
All M809s were built between 1970 and 1982. In 1982 the series was improved into the M939, and the first 11,000 M939s were rebuilds of M809 trucks rather than new vehicles.
Chassis and running gear
The M809 rides on a ladder frame with three live axles: the front on leaf springs, the rear tandem on leaf springs with locating arms. Three wheelbases were offered — short for tractors and dumps, standard for cargo trucks and wreckers, and extra long for long cargo bodies and expansible vans. Brakes were air over hydraulic with drums on all wheels, and most trucks had a rear pintle hitch able to tow a 15,000 lb trailer. A front-mounted 20,000 lb winch was a common option; it weighed 665 lb and added about 15½ inches to the length. The cab was the standard military pattern designed by REO for its 2½-ton M35, with hinged doors, a folding windscreen and a removable canvas roof.
Design and features
- Cummins NHC250: a conservative commercial diesel that was more powerful and less stressed than the multifuel engine of the M39.
- Automatic front axle engagement: the Rockwell-Standard transfer case engaged the front axle whenever the rear wheels turned faster than the front.
- Three wheelbases: from 167 to 215 inches, covering cargo, wrecker, dump and tractor bodies.
- Fifth-wheel towing: the M818 and M819 could haul semi-trailers of up to 37,500 lb.
AM General M809 versions
- M813 and M814: cargo trucks with a 14 ft box, or a 20 ft box on the extra-long M814; the M813A1 had drop sides for forklift loading.
- M815: bolster logging truck for logs, poles and pipes, with a matching bolster trailer.
- M816: medium wrecker with a rotating, telescoping boom lifting up to 20,000 lb.
- M817: dump truck with a 5 cubic yard body and a tailgate hinged at either end.
- M818: tractor unit for semi-trailers up to 37,500 lb.
The M809 was the direct ancestor of the M939 series, and it used the cab of the M35. Other military trucks are in the AM General collection.
Video: 1971 Am General M813
Video on YouTube.
Sources
- M809 series 5-ton 6×6 truck, English Wikipedia: history, engine, chassis, models
