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| Illustration 1 | g06356925 |
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(1) Transmission ECM
(2) Transmission (3) Operator controls (4) Solenoid valve (5) Drive shaft (6) Differential (7) Final drives (8) Tandems (9) Wheels | |
The transmission electronic control module (ECM) (1) is on the rear of the transmission (2). The ECM receives signals from the operator controls (3) as well as speed sensors and pressure sensors on the transmission. The operator may manually shift the transmission or allow the transmission to shift automatically.
The transmission ECM regulates the shifting of gears. The ECM shifts gears by modulating the appropriate solenoid valve (4) to engage the corresponding clutch inside the transmission. When the transmission is in manual mode, the ECM will not upshift or downshift automatically unless an engine overspeed or underspeed condition occurs.
When the ECM performs an upshift or downshift, the ECM moves shift solenoids in the clutch control valves. The valves regulate oil flow directly down the clutches inside the transmission.
The transmission has eight speeds forward and six speeds reverse. Transmission (2) is controlled by an electrical system and a hydraulic system. The selection of reverse, neutral, and forward is done manually. The transmission is an eight speed semiautomatic transmission.
The flow of power is from the engine to transmission (2). Power then goes from transmission (2) through drive shaft (5) to differential (6). Finally, the power goes through final drives (7), tandems (8) to wheels (9).