The Cat D11T and D11T Carrydozer come with design refinements that include enhanced auto shift, dynamic inclination monitor, automatic climate control and available automated ripper control. Their 850-net hp (634 kW) Cat C32 engines are fuel efficient, and with blades ranging in capacity up to 57 cu. yd. and operating weights up to 248,456 lbs., both machines can work productively in the toughest materials, according to the company. A new cooling package uses a two-part radiator with aluminum bar-plate cores that contribute to durability, efficient heat transfer and corrosion resistance. The new oil-to-air hydraulic-oil cooler uses similar construction, and a hydraulically variable demand fan uses less power, reduces fuel consumption and lowers sound levels. The D11T and D11T CD also feature an "OK-to-Start" system that electronically checks critical fluid levels. Routine maintenance is facilitated by easily accessed filters, an optional automatic lubrication system, high speed oil change for engine and power train systems, and ecology drains for capturing fluids for proper disposal or recycling.