[TechTalk]

The 1650 ft. lb. torque Detroit Diesel Series 60 engine became standard equipment in the spring of 2000, replacing the 1550 ft. lb. version. This 100 ft. lb. increase became available because Allison introduced an uprated version of the World Transmission. Previously, the transmission was restricted to a maximum of 1550 ft. lb. torque. The new transmission also carries a 5 year / 200,000 mile warranty instead of the previous 2 year warranty. The new engine continues to be rated at 500 hp @ 2100 r.p.m. Therefore, while the power output at the red line has not changed, the increased torque provides noticeably improved response at mid-range engine speeds where the engine is most often operating. We would like to use the 1800 ft. lb. torque, 550 hp version of the Series 60, but the Allison engineers get red faced and start hyperventilating every time we talk about it.