Specific: 7 tractors including
low-bed trailers received as MAP materiel in 1952. 2 nearly
identical versions, 3T1 and 17A1, were received.
Historical: The Caterpillar D7 was introduced as
model in 1938, and was equipped with the six-cylinder
D-8800 engine which developed 92 hp. The 20 inch wide
tracks were driven through a 5-speed gearbox. Maximum
drawbar pull was 10 tons.
US Army designation for the D7, which was a standard M1
heavy crawler, was "Tractor, Full-Tracked,
Low-Speed, DED, Medium DBP". Used for general
bulldozing, pan pushing, tree dozing, scraper towing and
other types of construction work.
The 3T1 version, which was produced between 1944 and
1955, was US Army's standard dozer widely used in all
theatres during WW II.
Apart from the above mentioned tasks, the D7 could be
used as tractor for a 240 mm howitzer and 155 mm field
Demand for the D7 was such that some 1000 examples were
also produced by American Car and Foundry to supplement
production from Caterpillar´s East Peoria plant.
The D7 and D8 tractors were frequently fitted with
armoured cabs that allowed them to be used by US Army
Engineers working in hostile environments. Among others,
the Union Metal Manufacturing Company produced a
purpose-built armoured cab for the two machines which
gave protection against small arms fire and shell
Similar machines were build by Allis-Chalmers, Cleveland
Length: 4.10 m (160 inches), w/dozer 5.80 m (226
Width: 2.50 m (97 inches), w/dozer 4.10 m (160
Height: 2.44 m (96 inches).
Weight: 14.341 kg (31.870 lb.).
Engine: Caterpillar 4-cylinder, type D8800, 13.618
cm3 (831 cubic inches) liquid cooled.
Horsepower: 92 at 1.050 rpm.
Transfer case: 2-speed.
Electrical system: 6 volt.
without preparation: N/A.
Fuel type: Diesel.
Fuel capacity: 246 liter (54 gallons).
Additional: A 2-cylinder vertical
gasoline engine was fitted to the left hand side of the
diesel engine. This starting engine could be started from
either top of engine hood, from the front or from
side. The starting engine exhaust pipe provide
preheating for main engine intake air. The machine are
fitted with Le Tourneau cable controls: Either a front
mounted single drum cable control for bulldozer only or a
rear mounted double drum cable control for scraper alone
or bulldozer. Some machines with front cable
control have rear mounted Hyster D7N 15 ton winch .
Caterpillar D7C (155 kb)