Shifter A/T: Description and Operation

External Controls

COMPONENT LOCATION









INTRODUCTION
The external controls for the transmission consist of a selector lever assembly, a selector cable, a selector lever position display and a M/S display.
The selector cable transmits the position of the selector lever to the transmission.
The selector lever positions are displayed on the selector lever position display and the M/S display. The selector lever position and current forward gear are also displayed in the instrument cluster. For additional information, refer to Transmission Description Description and Operation

SELECTOR LEVER ASSEMBLY









The selector lever assembly is located in the floor console. A bracket on the transmission tunnel provides the mounting for the selector lever assembly. A leather gaiter seals the gap between the selector lever and the trim of the floor console.
The selector lever positions are as follows:
- P (park) : no torque transmitted to the drive wheels and prevents the vehicle from moving by locking the transmission
- R (reverse) : selects reverse gear - only to be selected when the vehicle is stationary and the engine is at idle
- N (neutral) : no torque transmitted to the drive wheels - allows the vehicle to roll, so ensure the EPB (electronic parking brake) is applied before leaving the vehicle in this state
- D (drive) : this position uses all six forward gears in automatic operation
- M/S (manual/sport) : this position engages the sport mode, which uses all six forward gears as in D, but will upshift at higher engine speeds improving acceleration
- + and - : initiates upshifts and downshifts respectively, allowing the transmission to be used as a sequential manual transmission (CommandShift mode) with six forward gears.
The selector lever assembly has a cast mounting plate which provides for the location of the selector components. The selector lever is connected to a gimbal mechanism which allows for the selection of P, R, N, D in a forward or backward direction and, when D is selected, selection between D and M/S in a left/right direction. In the M/S position, the selector lever can be moved in a forward or backward direction to select + or - for manual (CommandShift) operation.
The mounting plate also houses the following components:
- Manual +/- CommandShift switch
- Shift interlock solenoid
- Selector lever position switch
- Manual/Sport switch
- Park lock solenoid
- Park lock switch.
A release button on the head of the selector lever operates a plunger, which rests on a cam at the base of the selector lever. Pressing the release button raises the plunger clear of the cam. The cam profile is such that the release button must be pressed to move the selector lever into and out of the P, and from N to the R positions.

Manual +/- CommandShift Switch
The manual +/- switch is located on the LH (left-hand) side of the selector lever assembly. The switch comprises a housing which provides the location for a sliding contact. When the selector lever is moved to the M/S position, a dog on the selector lever engages with a slotted abutment on the sliding contact. When the selector lever is moved to the + or - position the dog moves the sliding contact, which completes a momentary ground circuit with one of two microswitches at each end of the switch, which correspond to the + or - positions.
This momentary signal is received by the TCM (transmission control module), which, on first operation of the switch, initiates manual mode and operates the transmission in the selected gear.
In this position, a spring moves the selector lever to the center position when released.

Shift Interlock Solenoid
The shift interlock solenoid is located at the front of the selector lever assembly. The selector lever is connected to a locking plate which has two holes that correspond to the P and N positions. When the ignition is on and the selector lever is in the P or N position, the solenoid is energized by the TCM (transmission control module). When energized, the solenoid ejects a pin which engages in the locking plate, preventing the lever from being moved.
When the footbrake is applied, the ECM (engine control module) sends a high speed CAN (controller area network) message to the TCM (transmission control module), which de-energizes the solenoid allowing the lever to be moved from the P or N position. This prevents the selector lever from being moved to the D or R position unintentionally and the application of the brakes also prevents the vehicle 'creeping' when the gear is engaged.

Selector Lever Position Switch
The selector lever position switch is located on the RH (right-hand) side of the selector lever assembly. The switch has a moving contact which is connected to the selector lever. As the selector lever is moved, the sliding contact moves in the switch and, in turn, completes a circuit with four further contacts in the switch, which represent the four lever positions P, R, N and D. The switch is connected to the selector lever position display via a ribbon cable and provides the ground connection for the LED (light emitting diode)'s under the P, R, N and D symbols.

Manual/Sport Switch
The M/S switch is a cam operated microswitch located at the rear of the selector lever assembly. A lever with a roller is attached to the body of the M/S switch. When the selector lever is moved between the D and M/S positions, the roller rides along a cam on the selector lever, which operates the switch. When the selector lever moves from the D position to the M/S position, the M/S switch closes. When the selector lever moves from the M/S position to the D position, the M/S switch opens.
The M/S switch is installed in a ground circuit from the TCM (transmission control module). The TCM (transmission control module) operates the transmission in the sport mode when the M/S switch is closed and in the normal automatic mode when the M/S switch is open. When closed, the M/S switch also provides a ground for the M/S display, to illuminate the M/S symbol.

Park Lock Switch
This switch detects that the park lock lever has engaged in the selector mechanism and allows the P position to be confirmed both inside the transmission and at the selector lever. This signals to the TCM (transmission control module) that shutdown is allowable following an ignition off sequence. Failure to activate this switch will result in a flashing P in the transmission status display of the instrument cluster and the TRANSMISSION NOT LOCKED IN PARK warning in the message center on ignition off, with the TCM (transmission control module) still alive for up to 10 minutes or until the vehicle is locked.

Park Lock Solenoid
The park lock solenoid is part of a normally locked selector lever mechanism which requires the ignition on to unlock. This solenoid prevents movement of the selector lever from the P position in the ignition off state, to prevent vehicle roll-away due to inadvertent operation. This solenoid is energized continuously with the ignition on.

SELECTOR CABLE
The selector cable is a Bowden cable that connects the selector lever to the gear change lever on the RH (right-hand) side of the transmission. A clip secures the outer cable to the mounting plate of the selector lever assembly. The inner cable is secured to an arm which is connected to the selector lever via a U shaped bracket and pin.
The transmission end of the outer cable is secured to a bracket on the transmission by a clamp nut. The inner cable is attached to the gear change lever by a clamp bush and locknut, which provide a means of adjustment for the selector cable.
A grommet seals the selector cable where it passes through the transmission tunnel.

SELECTOR LEVER POSITION DISPLAY
The selector lever position display is located in the trim of the floor console, to the right of the selector lever. The display contains the symbols P, R, N and D, with a red LED (light emitting diode) under each symbol. When the ignition is on, the appropriate symbol is illuminated to indicate the position of the selector lever.
The four LED (light emitting diode) have a common power feed from the M/S display and individual ground connections with the selector lever position switch. At any one time, the selector lever position switch connects to ground only the LED (light emitting diode) under the symbol that corresponds to the position of the selector lever.

MANUAL/SPORT DISPLAY
The M/S display is located in the trim of the floor console, to the left of the selector lever. The display contains the symbol M/S, with a red LED (light emitting diode) under the symbol. When the ignition is on, the symbol is illuminated when the selector lever is in the M/S position.
The LED (light emitting diode) has a power feed from the ignition relay in the CJB (central junction box) and a ground connection with the M/S switch. The M/S switch connects the LED (light emitting diode) to ground only when the selector lever is in the M/S position.

CONTROL DIAGRAM

NOTE:
A = Hardwired.