The engine delivers 606 hp (447 kW) of power at 2100 rpm and a peak torque of 1950 lb ft (2644 Nm) at 1300 rpm. Other key components include the 18-speed Fuller RTLO-22918B transmission with a high-speed first gear ratio of 14.4:1 to 0.73:1. The rear axles are Axle Tech STRC-1297 hub reduction (former Rockwell all-terrain model) with a final ratio of 9.59:1. The front axle is a 295mm-deep chassis with a much thicker web and flange than the 9.1-tonne Rockwell FL941 and its highway cousins, and features a full-length dual-frame. These electric trailer units have a Smith-made body on a power-trans chassis (the company that made the powerful trailer unit) and are equipped with 450 and 500 horsepower Cummins ISX or Signature engines. They are coupled to an Allison automatic transmission and three-drive SISU hub reduction axles. Control of these trailers is linked to both a cab-mounted hand throttle and the accelerator pedal. This has the advantage, for example, that the trailer can be set to full throttle when the unit is climbing a hill, and there is minimal loss of road speed when the driver changes gear on the Kenworth C510 while the trailer continues to push the unit.