- Transmission Electronic Control Module
- Torque Converter
- Transfer Gears and Transmission
- Differential and Final Drives
The four basic systems have a hydraulic connection, an electrical connection, a magnetic connection, or a mechanical connection.
The Transmission electronic control module (Transmission ECM) matches the transmission speed to the selected speed of the transmission shift lever. The Transmission ECM gets information of the selected speed of operation through the electrical system. The Transmission ECM activates the transmission hydraulic system through the modulating valve solenoids for the transmission. The torque converter hydraulic system controls the modulating valve solenoid for the torque converter lockup clutch.
The Transmission ECM controls the following items:
- Transmission shifting
- Engine overspeed protection
- Neutral coast inhibiting
- Fail in gear protection
- Shift Torque Management (STM)
- Reverse shift inhibiting
- Anti-hunt
- Directional shift management
- Shift counter
- Top gear limit
- Torque converter lockup
The torque converter has a lockup clutch for direct drive and a one-way clutch for torque converter drive. The torque converter is fastened directly to the flywheel of the engine.
The torque converter drives the transmission hydraulically, unless the lockup clutch is activated. When the lockup solenoid is activated, the lockup clutch is hydraulically engaged. The torque converter rotating housing is now mechanically connected to the output shaft of the torque converter. The drive shaft mechanically connects the torque converter to the transfer gears. The transfer gears are fastened directly to the transmission.
The modulating valve solenoids for the transmission hydraulically activate the transmission hydraulic control valves. The control valves activate the transmission clutches which cause the mechanical connection to the transmission output shaft. The clutches in the transmission will not drive the transmission output shaft unless the torque converter is activated hydraulically or mechanically.
The transmission has six forward speeds and one reverse speed. The selection of speed is done manually in REVERSE, in NEUTRAL and in FIRST. The selection of SECOND through SIXTH speeds is done automatically.
Power is sent through the REVERSE gear in torque converter drive only. FIRST has both a torque converter drive and a direct drive. SECOND through SIXTH speeds is direct drive with a short time of converter drive during transmission clutch engagement. The direct drive with a short time of converter drive enables smoother shifts. The transmission is fastened directly to the differential and bevel gear. The differential and bevel gear are fastened directly to the rear axle housing. The differential and bevel gear are also connected to the rear axle. The rear axle is connected to the wheels and final drives.
After the transmission is connected to the torque converter, power flows from the engine through the torque converter and the transmission to the differential. The rear axles mechanically connect the differential to the final drives. The final drives are connected to the rear wheels. Power is then sent to the tires.
Pressure oil that is used to engage the lockup clutch comes from the gear pump for the transmission and torque converter. Oil flows through the oil filter to the modulating valve for the torque converter lockup clutch. The modulating valve for the torque converter lockup clutch controls the operation of the lockup clutch.
The transmission has a separate hydraulic system, which uses oil from the torque converter sump. The following components are part of this hydraulic system:
- Transmission hydraulic control group
- Gear pump (transmission charging section and transmission scavenge section)
- Transmission charging hydraulic filter
- Magnetic screen
- Transmission oil cooler
The following components are part of the transmission hydraulic control group:
- Modulating valves for the transmission clutch
- Main relief valve
- Transmission lubrication relief valve
Note: The solenoids on the modulating valves for the transmission clutches are the connection between the electrical system and the hydraulic system.
The solenoid valve on each modulating valve regulates the oil to the clutches . These solenoids are electrically activated. The modulating valves for the transmission clutches then send oil at the correct rate to engage the proper clutches in the transmission.
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| Illustration 1 | g06234571 |
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Neutral position (1) Magnetic screen (Torque Converter) (2) Full Flow Filter (Torque Converter) (3) Torque Converter Filter Bypass Switch (power train) (4) Bypass Switch (oil filter) (5) Temperature Sensor (transmission oil) (6) Modulating Valve (transmission hydraulic control) (7) Modulating valve (Torque Converter lockup clutch) (8) Main relief valve (9) Torque Converter (inlet relief valve) (10) Torque Converter (11) Drive Box Pump (12) Oil Cooler (power train) (13) Lubrication Relief Valve (14) Transmission Lubrication (15) Speed Sensor (transmission input) (16) Speed Sensor (transmission intermediate 1) (17) Speed Sensor (transmission intermediate 2) (18) Speed Sensor 1 (transmission output) (19) Speed Sensor 2 (transmission output) (20) Full Flow Filter (Control Pump) (21) Torque Converter Sump (22) Transmission Control (23) Transmission ECM (24) Chassis ECM (25) Scavenge Screen (26) Scavenge Pump (27) Torque Converter Pump (28) Controls Pump (29) RAX Pump (30) Magnetic Screen (31) Magnetic Screen (32) Sump (Dry) (33) Torque Converter Bypass Switch | |
When Transmission control (22) is moved to the NEUTRAL position, the position sensor on Transmission control (22) sends a PWM signal to Chassis ECM (24). The Chassis ECM (24) is linked to the Transmission ECM (23) by the "Requested Gear Command" signal line. The Transmission ECM interprets the PWM signal as an operator request to move the transmission to NEUTRAL. Due to the NEUTRAL request, Transmission ECM (23) sends a signal to modulating valve (6) for the first clutch to engage. The signal activates the solenoid valve that moves a spool which redirects the oil in modulating valve (6). The oil is sent to the first clutch inside the planetary transmission. In neutral with only the first clutch engaged, neither directional clutch is energized.
When the transmission is in the NEUTRAL position, oil is drawn from the torque converter sump, through magnetic screen (1) by gear pump (2). Gear pump (2) sends oil through oil filter (3) and to the transmission hydraulic control.
Remaining hydraulic oil continues to flow through the system and back to the torque converter sump.
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| Illustration 2 | g06237523 |
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Reverse position (1) Magnetic screen (Torque Converter) (2) Full Flow Filter (Torque Converter) (3) Torque Converter Filter Bypass Switch (power train) (4) Bypass Switch (oil filter) (5) Temperature Sensor (transmission oil) (6) Modulating Valve (transmission hydraulic control) (7) Modulating valve (Torque Converter lockup clutch) (8) Main relief valve (9) Torque Converter (inlet relief valve) (10) Torque Converter (11) Drive Box Pump (12) Oil Cooler (power train) (13) Lubrication Relief Valve (14) Transmission Lubrication (15) Speed Sensor (transmission input) (16) Speed Sensor (transmission intermediate 1) (17) Speed Sensor (transmission intermediate 2) (18) Speed Sensor 1 (transmission output) (19) Speed Sensor 2 (transmission output) (20) Full Flow Filter (Control Pump) (21) Torque Converter Sump (22) Transmission Control (23) Transmission ECM (24) Chassis ECM (25) Scavenge Screen (26) Scavenge Pump (27) Torque Converter Pump (28) Controls Pump (29) RAX Pump (30) Magnetic Screen (31) Magnetic Screen (32) Sump (Dry) (33) Torque Converter Bypass Switch | |
When Transmission control (22) is moved to the REVERSE position, the position sensor on Transmission control (22) sends a PWM signal to Chassis ECM (24). The Chassis ECM (24) is linked to the Transmission ECM (23) by the "Requested Gear Command" signal line. The Transmission ECM (23) interprets the PWM signal as an operator request to move the transmission to REVERSE. Due to the REVERSE request, Transmission ECM (23) sends a signal to modulating valve (6) for the first clutch and the sixth clutch to engage. The signal activates the solenoid valves that move a spool which redirects the oil in modulating valves (6). The oil is sent to the first and sixth clutches in the planetary transmission. In reverse with the first and sixth clutches engaged, the power train is in converter drive only.
When the transmission is in the REVERSE position, oil is drawn from the torque converter sump, through magnetic screen (1) by gear pump (2). Gear pump (2) sends oil through oil filter (3) and to the transmission hydraulic control.
Remaining hydraulic oil continues to flow through the system and back to the torque converter sump.
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| Illustration 3 | g06237531 |
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First Gear position (1) Magnetic screen (Torque Converter) (2) Full Flow Filter (Torque Converter) (3) Torque Converter Filter Bypass Switch (power train) (4) Bypass Switch (oil filter) (5) Temperature Sensor (transmission oil) (6) Modulating Valve (transmission hydraulic control) (7) Modulating valve (Torque Converter lockup clutch) (8) Main relief valve (9) Torque Converter (inlet relief valve) (10) Torque Converter (11) Drive Box Pump (12) Oil Cooler (power train) (13) Lubrication Relief Valve (14) Transmission Lubrication (15) Speed Sensor (transmission input) (16) Speed Sensor (transmission intermediate 1) (17) Speed Sensor (transmission intermediate 2) (18) Speed Sensor 1 (transmission output) (19) Speed Sensor 2 (transmission output) (20) Full Flow Filter (Control Pump) (21) Torque Converter Sump (22) Transmission Control (23) Transmission ECM (24) Chassis ECM (25) Scavenge Screen (26) Scavenge Pump (27) Torque Converter Pump (28) Controls Pump (29) RAX Pump (30) Magnetic Screen (31) Magnetic Screen (32) Sump (Dry) (33) Torque Converter Bypass Switch | |
When Transmission control (22) is moved to the FIRST position, the position sensor on Transmission control (22) sends a PWM signal to Chassis ECM (24). The Chassis ECM (24) is linked to the Transmission ECM (23) by the "Requested Gear Command" signal line. The Transmission ECM (23) interprets the PWM signal as an operator request to move the transmission to FIRST. Due to the FIRST position request, the Transmission ECM (23) sends a signal to modulating valve (6) for the first clutch and the fifth clutch to engage. The signal activates the solenoid valves that move a spool which redirects the oil in modulating valves (6). The oil is sent to the first and fifth clutches in the planetary transmission. In first gear with the first and fifth clutches engaged, the power train is in converter drive below
When the transmission is in the FIRST position, oil is drawn from the torque converter sump, through magnetic screen (1) by gear pump (2). Gear pump (2) sends oil through oil filter (3) and to the transmission hydraulic control.
The power train only in direct drive for second through sixth speeds. Torque converter (10) moves to converter drive between each shift to provide smooth shifting.
Remaining hydraulic oil continues to flow through the system and back to the torque converter sump.
Remaining speeds, two through seven, operate similarly to FIRST position, but in strictly direct drive and with different clutches engaged.