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M37 Gun Motor Carriage (GMC)

Self-Propelled Gun (SPG)

M37 Gun Motor Carriage (GMC)

Self-Propelled Gun (SPG)


Appearing similar to the M7 Priest, the M37 mated the gun of the M4 Sherman 105 series with the chassis of the M24 Chaffee light tank.
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ORIGIN: United States
YEAR: 1945
MANUFACTURER(S): General Motors - USA
OPERATORS: Spain; United States

Unless otherwise noted the presented statistics below pertain to the M37 Gun Motor Carriage (GMC) model. Common measurements, and their respective conversions, are shown when possible.
LENGTH: 17.98 feet (5.48 meters)
WIDTH: 9.68 feet (2.95 meters)
HEIGHT: 8.04 feet (2.45 meters)
WEIGHT: 25 Tons (23,000 kilograms; 50,706 pounds)
ENGINE: 2 x Cadillac Series 44 V8 gasoline engine developing 220 horsepower.
SPEED: 30 miles-per-hour (48.28 kilometers-per-hour)
RANGE: 100 miles (161 kilometers)


1 x 105mm main gun
1 x 0.50 caliber anti-aircraft heavy machine gun

126 x 105mm projectiles
550 x 0.50 caliber ammunition

Series Model Variants
• M37 - Base Series Designation based on the chassis of the M24 Chaffee Light Tank.
• 105mm Gun Motor Carriage M37 - Full Formal Designation.


Detailing the development and operational history of the M37 Gun Motor Carriage (GMC) Self-Propelled Gun (SPG).  Entry last updated on 3/21/2016. Authored by Staff Writer. Content ©
The M37 Gun Motor Carriage was a self-propelled gun of the American military appearing towards the end of World War 2. The type was developed from the existing chassis of the M24 Chaffee Light Tank as a faster, lighter alternative to the heavier, slower M7 "Priest". Initial examples were delivered in 1945, the last year of the war. Despite this, the M37 missed out on combat actions in the war altogether though it managed to remain in inventory into the Korean War (1950-1953). Total production ultimately reached 316 units of the 448 originally ordered, all delivered from General Motors.

The original M25 Chaffee ("Light Tank M24") appeared in 1944 and saw 4,731 units produced into August of 1945. It was used extensively in the closing months of World War 2 in the light tank role, supporting infantry actions and reconnoitering enemy positions and movements. The M24 was intended to replace (and ultimately improve upon) the preceding M3/M5 Stuart light tanks. The Chaffee was therefore armed with a capable 75mm M6 L/40 main gun, 1 x 0.50 caliber Browning M2HB heavy machine gun and 2 x .30-06 Browning M1919A4 general purpose machine guns. The hull was stout, each side straddled by exposed running gear consisting of five double-tired road wheels, front-mounted drive sprocket and rear-mounted track idler. Three track return rollers were identified along the upper track sections. The standard operating crew was five personnel and power was supplied by way of 2 x Cadillac Series 44T24 8-cylinder engines developing 110 horsepower each. When utilized against lightly-armored or unprotected vehicles and in the fast reconnaissance role, the little M24 excelled thanks to inherently good mobility and speed. Its light armor protection made it susceptible to enemy tank and anti-tank crews in turn so tanker crews needed to exercise care with each engagement.

As a conversion of the M24, the M37 incorporated the same running gear with an all-new, fixed open-air superstructure. The M37 itself was developed to replace the M7 "Priest" which themselves were built upon the medium-class M3 Lee / M4 Sherman tanks being fielded en mass during the war (prior to the arrival of the war-winning M4 Sherman). While the M7 mounted the capable "105mm M1/M2" howitzer gun system (based on the successful M101 field howitzer), the M37 was afforded the similar "105mm M4" model (also based on the M101, the same as fitted to howitzer-armed Shermans). The hull superstructure was given a right-side mounted machine gun "pulpit" as seen the M7 Priest series before it. The 105mm gun was settled in a mounting near the vehicle's centerline (slightly offset to right). The remainder of the design consisted of an open-topped armored tub which encompassed the gunnery crew's fighting compartment (only the driver was protected from the elements). Like other vehicles of this type, armor protection was deemed thin and useful only against small arms fire and artillery spray. The main gun traversed in its mounting across a 52-degree arc which required the entire vehicle to be turned in the direction of fire beyond this limit. Up to 126 x 105mm projectiles were carried. A 0.50 Browning M2HB heavy machine gun was fitted to the pulpit for anti-aircraft/anti-armor defense. The vehicle was crewed by seven personnel including the driver, commander, gunners and ammunition handlers. Power was served through 2 x Cadillac Series 44 V8 gasoline fueled engines developing 220 horsepower each. Top road speed was 48 kmh with an operational range of 161 km. The vehicle weighed in at 23,000 kg.

While the original M24 design proved a fast, nimble armored system, the M37 was stricken with a heavier weight load along its top, consisting of the 105mm howitzer, its required mounting and recoil system, available ammunition stores and the armor required of the fighting compartment. This modification removed much of the beneficial tactical qualities inherent in the M24 design, making for a much slower, more plodding tracked system. Regardless, the M37 was never intended for frontline direct fire - instead relegated to behind-the-lines indirect fire support of advancing units.

With the end of the Korean War, the M37 GMC joined other World War 2-era systems in mothballs and eventual retirement (including the M4 Sherman). The Spanish Army was one recognized foreign recipient of the M37 Gun Motor Carriage system.