L322 Range Rover System Description and Operation
AUTOMATIC TRANSMISSION – ZF 5HP24
44-2-38 DESCRIPTION AND OPERATION
The selector lever comprises a cast mounting plate which provides for the location of the selector components. The
lever is connected to a gimbal mechanism which allows for the selection of P, R, N, D is a forward or backward
direction and selection between automatic and manual/sport in a left/right transverse direction. When manual/sport
mode is selected, the lever can be moved in a forward or backward direction to select + or – for manual (Steptronic)
operation.
When the selector lever is moved to the M/S position, the Bowden cable to the transmission is mechanically
disconnected at the shifter. If left in Sport mode all gear changes are performed automatically. If Manual (Steptronic)
mode is selected, all gear changes are based on switched ground inputs received by the EAT ECU from the Manual
+/– Steptronic switch.
The selector lever mechanism houses the following components:
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Manual +/– Steptronic switch
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Shift interlock solenoid
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High/Low range selector switch
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Hill Descent Control (HDC) switch
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Selector position LED display
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Selector lever position switch
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Manual/Sport switch
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Key interlock mechanism.
There are four selector lever positions and two additional positions for manual/sport operation:
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P ( Park) – Prevents the vehicle from moving by locking the transmission
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R (Reverse) – Select only when the vehicle is stationary and the engine is at idle
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N (Neutral) – No torque transmitted to drive wheels
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D (Drive) – This position uses all five forward gears in high and low ranges
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M/S (Sport mode) – This position uses all five forward gears as in 'D', but will upshift at higher engine speeds
improving acceleration
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+ and – (Manual 'Steptronic' mode) – Movement of the selector lever in the +/– positions, when the lever is in
the M/S position, will operate the transmission in manual (Steptronic) mode, allowing the driver to manually select
all five forward gears.
The selector lever position is displayed to the driver on the selector position LED display and in the instrument
pack. In 'Steptronic' mode, if a gear is selected but the EAT ECU logic prevents selection of that gear, the
requested gear will be initially displayed. The EAT ECU will engage the next allowed gear and then display that
gear.
Manual +/– Steptronic Switch
The manual +/– switch is located on the 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 manual/sport position, a dog
on the lever engages with a slotted abutment on the switch sliding contact. When the lever is moved to the + or –
position the dog moves the switch completing a momentary earth 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 EAT ECU which, on first operation of the switch, initiates manual mode and
operates the transmission in the selected gear.
In this position, a spring will move the selector lever to the centre 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 which correspond to the 'P' and 'N' positions. When the ignition is on or the engine
is running, the solenoid is energised by the EAT ECU when the selector lever is in the 'P' or 'N' positions. When
energised, the solenoid ejects a pin which engages in the locking plate preventing the lever from being moved.
When the footbrake is applied, a signal from a brake switch is passed to the EAT ECU which de-energises the
solenoid allowing the lever to be moved from the 'P' or 'N' position. This prevents the selector 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.
Movement of the selector lever from the 'P' or 'N' positions is also prevented if the EAT ECU senses that the engine
speed is above 2500 rev/min, even if the brake pedal is depressed.
