John Deere's 250D, 300D, 350D and 400D ADTs have been enhanced to increase productivity and uptime, including updates to the transmission, operator station improvements, electrical enhancements and a new engine in the 250D and 300D.

The 350D and 400D ADTs are powered by a turbocharged and intercooled Mercedes Benz OM501LA 12-liter V6 diesel that meets EPA Tier-3 emissions standards. According to the company, the compact engine allows these trucks to offer a best-in-class approach angle. The 250D and 300D also feature a Tier 3-certified diesel, in this case a 24-valve John Deere 6090 PowerTech Plus I6. Engine displacement has increased from 8.1 to 9 liters. The transmission, updated in all four models, offers improved shift quality and clutch control. The 250D and 300D cooling system also provides greater transmission cooling capacity.

Cab features include a fully adjustable air-suspension seat, more sound insulation and a high-capacity air conditioner. A new monitor provides increased diagnostic capability, and a new sealed switch module with centralized controls eliminates several rocker switches, a retarder lever and mechanical heating and ventilation controls. A relocated electrical center provides easy access to fuses, relays and controllers. Only four relays remain in the electrical center.

A driveline assist feature automates some repetitive tasks during dumping. It shifts the transmission to neutral, applies the parking brake and takes the engine to maximum speed when the dump body lever is in the full dump position. Once the maximum dump angle is reached, the engine returns to low idle travel.

A new electrohydraulic tip control allows the operator to set maximum dump-body tip height and specify either soft or hard stops at the end of dump-body travel. According to a Deere spokesman, “Sticky material applications may require mechanical hard stops to minimize carry-back, but for other applications that don't require hard stops, the electrohydraulically controlled soft stop reduces machine structural loads and improves operator comfort.”