CORE AS-OIL COOLER 3656875 - Caterpillar

Transmission/Chassis ECM controls the torque converter lockup. When the ECM activates the lockup solenoid, the lockup clutch in the torque converter mechanically connects the torque converter input shaft to the torque converter output shaft. This linkage efficiently connects the power train to the engine. The ECM keeps the lockup clutch engaged as much as possible during normal operation. When the transmission shifts, the lockup solenoid is deactivated momentarily for smoother shifting. The machine is in torque converter drive when the lockup solenoid is deactivated. The transmission gears (reverse and neutral) are only torque converter drive. First gear is torque converter drive at low ground speeds, and direct drive at high ground speeds. The transmission gears (two through six) are direct drive only.