John Deere has added the new 450K and updated 550K and 650K dozers to its crawler dozer lineup. The 450K boasts a John Deere 4.5L Final Tier 4 diesel engine with 80 hp. The latest crawler addition delivers 16 per cent more horsepower along with a more impressive power-to-weight ratio, available torque and draw bar pull than its J-Series counterpart. It also features Eco Mode that regulates engine RPM and the hydrostatic transmission to burn up to 20 per cent less fuel in a wide range of applications. The addition of Total Machine Control enables an operator to customise control of decelerator mode and response, forward/reverse ground speed, steering modulation, forward/reverse speed ratios and even record machine usage. The updated 550K and 650K dozers incorporate a John Deere 4.5L Final Tier 4 diesel engine with 92 hp and 104 hp, respectively. The 550K features six undercarriage rollers versus the 650K?s seven, and 86 inch of track on the ground versus the 650K?s 92. An efficient, friction-eliminating direct-drive fan on the 450K and 550K models is easy and less costly to maintain. A cool-on-demand variable-speed fan on the 650K runs only as needed, reducing fuel consumption, and includes an optional reversing feature to aid cooler cleanliness in high debris environments.