Mack M123 tractor truck and M125 truck
| M123 and M125 10-ton 6x6 truck | |
|---|---|
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M123 Semi-tractor
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| Type | 10‑ton 6x6 trucks |
| Place of origin | United States |
| Production history | |
| Designer | Mack |
| Manufacturer | Mack, CONDEC |
| Produced | 1955–1969 |
| Number built | 3580 (+552 M125) |
| Specifications (M123) | |
| Weight | 32,490 lb (14,740 kg) empty |
| Length | 23 feet 4 inches (7.11 m) |
| Width | 9 feet 6 inches (2.90 m) |
| Height | 9 feet 3 inches (2.82 m) |
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| Engine | Le Roi TH-844 (for other see text) 297 hp (221 kW) |
| Transmission | 5 speed x 2 range |
| Suspension | Beam axles on leaf springs |
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Operational
range |
300 mi (482.8 km) |
| Speed | 42 mph (68 km/h) |
The Mack M123 (G792) was a 10-ton 6x6 semi-tractor introduced in 1955; the Mack M125 was a heavy cargo truck version of the M123. The M123 was used to tow tank transporter trailers while the M125 towed field artillery pieces.
In 1949 the US Army set a requirement for a family of extra heavy-duty 10‑ton (9,072 kg) off-road load rated 6x6 tactical trucks. Mack’s design, influenced by their WWII era NO, was chosen. Designed as an entire family, only the semi-tractor and cargo/prime mover were built. 392 M123s were built between 1955 and 1957 and 552 M125s in 1957 and 1958.
In 1965 CONDEC began building 3188 diesel powered M123As, Mack began building 420 in 1968. In 1969 Mack then upgraded 210 gas engine models to diesel power.
With the Army using more self‑propelled artillery, the need for prime movers was reduced, no follow‑up orders for M125s were made.
Both M123s and M125s saw service in the Vietnam War. M123 tractors remained in Army service into the 1990s.
In addition to the US Army, the M123 was used by the U.S. Marine Corps and exported to U.S. allies in such countries as Australia and Spain.
All M123s and M125 built in the 1950s had a LeRoi T‑H844 engine, a 844 cu in (13.8 L) overhead valve V 8 gasoline engine developing 297 hp (221 kW) at 2600 rpm and 725 lbf·ft (983 N·m) of torque at 1700 rpm. M123A1s built in the 1960s had a Cummins V8‑300, a 785 cu in (12.9 L) naturally aspirated V 8 diesel engine developing 300 hp (220 kW) at 3000 rpm and 580 lbf·ft (786 N·m) torque at 2100 rpm. This engine was also retrofitted into M123s to make M123E2s. No M125s were converted to diesel power.
The drivetrain was a repeat of that in the Mack NO, with a Mack TRDXT72 5 speed transmission with the transfer case mounted solidly to the rear of the transmission. This transmission was direct in 5th. The transfer case had a 2.50:1 low range, engaged the front axle, and had a power take-off to operate the winch(s).
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Wikipedia