This truck was manufactured by Mack in the late 1950s used primarily as the prime mover for towed 8-inch and 155mm artillery. The design borrowed many components from the WW II Mack NO 7 1/2 ton truck. The M-125 was in U.S. service through the 1980s. About 550 units were built.
The M-125 Truck, Cargo, 10-ton, 6x6 was powered by the LeRoi TH-844 V8 gas engine with 297bhp at 2600rpm. Its tires were 14:00x24 with dual wheels on the rear axles. It was equipped with air brakes and a 45,000 lb. front mounted winch,
Manuals for the M-125 10-ton 6x6 trucks were first produced before the modern system of manual numbering was introduced. Some of the original manuals were TM 9-8002 (1 November 1955) and ORD 7 SNL G792 Parts List (November 1955). Manuals from the new system will be numbered will be numbered TM 9-2320-206-xx where the xx represents the maintenance level.
Thanks to Corjan de Wit of Middelburg, the Netherlands, you will find TM 9-2320-206-12 (M123 and M125) at the linked page.
The M-125 Truck, Cargo, 10-ton, 6x6 was assigned NSN 2320-00-219-7340 and the M-125A1 NSN 2320-00-740-0493.