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Caterpillar D7 Bulldozer
The Caterpillar D7 series medium bulldozer began service with the U.S. military during World War II. With upgrades and changes, it has been a workhorse for the U.S. Military for over fifty years, fulfilling its primary earthmoving role as well as a host of other roles discovered for it, for example mine clearing with a special flail adapter kit. Although very versatile, the ability of the D7 to operate varies with soil conditions.
For the Army, the D7 dozer is the primary earthmover for construction of survivability positions and antitank ditches. It must be transported by trailer due to its poor mobility. Three dozers are assigned to corps combat engineer companies and CONUS divisional combat engineer companies. The other U.S. Military services have roles for the D7 in their operations around the world.
Models of the Caterpillar D7 Bulldozer
The Cat D7 bulldozer has had a long service life in the U.S. military, including these models:
The NSNs stated for the D7 models are typical, but many other NSNs were assigned for use by the U.S. service branches depending on optional equipment and other factors.
During WW II, the D7 was one of the bulldozers collectively known as "Tractor, Heavy, M1." The Caterpillar D7 models were Ordnance G-126. Equivalent tractors were produced during WW II by Allis-Chalmers Co. (Model HD10W, G-98) and International Harvester Co. (Model TD18, G-101). About one thousand Caterpillar D7s were also produced by American Car & Foundry under license when WW II military orders exceeded Caterpillar's capacity.
Caterpillar Tractor Co. produced the D7 until Caterpillar's military business was reorganized into Caterpillar Defense & Federal Products (Mossville, IL).
Caterpillar Model D7R Dozer
After more than 60 years, in the mid-2000s, the Caterpillar D7R became the latest D7 model to be modified for military use. The D7R is equipped with an elevated sprocket undercarriage for added durability and efficiency during earthmoving. The operator's station provides excellent observation of the blade and the rear of the machine for maximum operator productivity. Equipped with differential steer, its dual twist tiller provides for excellent maneuverability and one-handed, finger-tip directional, gear range, and steering controls with less operator fatigue. Interior noise levels are reduced to 83 dB, a level that does not require ear protection. Operational weight of the D7R dozer is 59,000 lbs. Military modifications include transport provisions, blackout lights and CARC paint.
Caterpillar D7 Dozer Characteristics
Note: The tabulated characteristics are based on the D7G model.
Manuals for the Caterpillar D7 include TM 9-1773 Heavy Tractor, M1 Caterpillar D7 Ordnance Maintenance (September 1943) and parts list SNL G-126. Modern manuals for the Tractor, Full Tracked, Low Speed DED are in the series TM 5-2410-237-xx depending on maintenance level.
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