thumb|300px|right|Caterpillar D10T
thumb|right|300px|Caterpillar D10N
The Caterpillar D10 is a bulldozer originally manufactured by Caterpillar between 1977 and 1987, when it was superseded by the D11; the successor of the smaller D9L was then rebranded as the D10N, which series of models continues to be produced (under the subsequent D10R, D10T, and—once again, as of 2023—D10 designations). It was the first modern tractor to use the elevated drive sprocket to improve durability, operator comfort, and ease of maintenance.
History
The Caterpillar D10 was the result of a need for a tractor larger than the Caterpillar D9. At this time, competitors were building bulldozers that were more powerful than the D9. Allis-Chalmers introduced at Conexpo 69 in Chicago a HD-41 which was the largest crawler in the world. In 1974 after Allis Chalmers and Fiat merged their construction equipment divisions, the 41-B was introduced. For example, the Fiatallis 41-B track-type tractor had at the time, while the D9H had . In 1976 Japanese company Komatsu came out with an even larger bulldozer called the D455A at and .
The first pilot D10 was D10X1 and was shown in July 1973 at a big Caterpillar corporate meeting. Other prototypes would follow in 1975 and 1977. In March 1977, prototypes P-1 through P-10 would appear and be subsequently dispatched to different job sites. The D10 was introduced at a dealer meeting by Caterpillar in the fall of 1977. Between 1978 and 1986 nearly 1,000 D10s were made at Caterpillar's East Peoria, Illinois, plant. The D10 had sales of their Fiatallis/Komatsu competitive sized bulldozers combined. With the introduction of the N-Series tractors in 1986-87 Caterpillar adjusted the model numbers of their larger bulldozers and pushed them up one, resulting in the D9N replacing the D8L, the D10N replacing the D9L, and the new D11N replacing the D10. A new D8N model was also introduced, smaller than the old D8L.
The D10 was large enough to do about 50 percent more production than the D9H.
High Drive system
thumb|300px|CAT D10N at work in [[Rishon LeZion, Israel]]
Among modern tractors, the High Drive (elevated sprocket) design was unique to Caterpillar products. The concept originated in 1914 with Caterpillar predecessor C. L. Best Tractor's 30 Humpback; this tractor was discontinued a year later, and the only other tractor to use the concept until the D10's introduction was the Cletrac Model F, built between 1920 and 1922. The elevated sprocket system was first applied to a 10-machine test run of the D10 in 1977. It separated the suspension from the tractor's drive train, dramatically reducing stress on both and increasing their durability. Prior to this, the combined system, which put the drive axle under constant strain of the vehicle's load and terrain beneath it, was prone to frequent failure. Elevating the drive sprocket allowed for a more absorbent suspension, which provided better traction, reduced component wear and operator fatigue,