The 630K Series wheel tractor-scrapers—631K and 637K—replace the previous 630G Series
The new Cat 620 K Series Wheel Tractor-Scrapers—621K, 623K, and 627K—refine the design of their H Series predecessors, which introduced features such as Sequence Assist and Load Assist that automate cycles.
The new Cat 621H, 623H and 627H wheel tractor-scrapers feature a more powerful engine in the tractor, and a more powerful engine in the scraper of the 627H.
Cat completely redesigned the tractor for its 613G scraper with a C6.6 engine delivering 3 percent more horsepower and a new torque converter increasing rim pull. With faster elevator and travel speeds, the 613G can load material as much as 13 percent faster than its predecessor.
Replacing the 657E, Caterpillar's 657G open-bowl scraper features Cat's C18 ACERT engine for the tractor and the C15 ACERT engine for the scraper. The largest of eight machines in the G Series wheel tractor-scrapers, the 657G has a heaped capacity of 44 cubic yards and a rated load of 104,058 pounds.