RETAINER 8E6207 - Caterpillar

Two different systems control the operation of the transmission. An electrical system activates the transmission hydraulic controls. The electronic control for the transmission permits manual shifts of the transmission and automatic shifts of the transmission. The operator manually moves transmission shift lever (1) in order to shift the transmission. The selection of REVERSE, NEUTRAL and FIRST speeds is done manually. The shift from FIRST speed to SECOND speed must be done manually. The selection of SECOND through EIGHTH speeds is automatic as a result of the position of transmission shift lever (1) and the rpm of the output shaft of the transmission. The electronic control system for the transmission will not permit the transmission to upshift to a speed higher than the position of the transmission shift lever. The control system will automatically downshift until SECOND speed is reached.
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Underneath Operator Compartment (2) Electronic control module (ECM)
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Right Side Of Seat (1) Transmission control lever (3) Shift lever switch (inside cover)The transmission electrical system is made up of the following components.
A solid-state transmission control (2)
A transmission switch (4)
A shift lever switch (3)
Two solenoids that control the shift and engagement of the transmission
A neutral start control
A transmission speed sensor (5)
A transmission hold control (switch) (6)
Electrical harnesses and connectorsThe neutral start control allows the tractor to start only in NEUTRAL.
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Left Side Of Tractor (4) Transmission switch (inside cover)
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Rear Of Tractor (5) Transmission speed sensor (inside cover)
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(6) Transmission hold control (switch)The main component in this electrical system is the transmission control. The transmission control must get information from four sources.
The switch for the transmission control (3)
The transmission switch (4)
The transmission speed sensor (5)
The transmission hold control (switch) (6) With the information from these components, the transmission control will send an electrical signal to the upshift solenoid (8) or downshift solenoid (7) .
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Top Of Transmission (7) Downshift solenoid (8) Upshift solenoidThe basic components of the transmission hydraulic controls are listed below.
two solenoids (7) and (8)
pressure control valve (9)
selector valve (10)
rotary actuator (11) The solenoids are the connection between the electrical system and the hydraulic system. When one of the solenoids is activated electrically, oil will flow to rotary actuator (11) . The rotary actuator turns a rotary selector spool in selector valve (10) which sends pilot oil to pressure control valve (9) . Pressure control valve (9) then sends oil at the correct rate in order to smoothly engage the correct clutches in the transmission.
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Right Side Of Transmission Hydraulic Controls (7) Downshift solenoid (8) Upshift Solenoid (9) Pressure control valve (10) Selector valve (11) Rotary actuator (12) Rotary selector shaftThe rotary selector spool can be manually moved through all of the positions when the engine is off. Rotary selector shaft (12) is connected to the rotary selector spool. When rotary selector shaft (12) is turned, the rotary selector spool turns. When rotary selector shaft (12) is rotated all the way clockwise, rotary actuator (11) is in NEUTRAL