AUTOMATIC TRANSMISSION 5A-21
Downshift Type
RANGE ‘1’ (MANUAL ‘1’):
RANGE ‘2’ (MANUAL ‘2’):
RANGE ‘3’ (MANUAL ‘3’):
RANGE ‘D’ (DRIVE):
RANGE ‘N’ (NEUTRAL):
RANGE ‘R’ (REVERSE):
RANGE ‘P’ (P ARK):Inhibited Above
First gear operation only with inhibited engagement as a function of vehicle speed. Engine braking is applied with reduced throttle.
First and second gear operation with inhibited engagement of second gear, as
a function of vehicle speed. Engine braking is applied with reduced throttle.
First, second and third gear operation with an inhibited third gear engagement
at high vehicle speed. Refer to the vehicle owner’ s manual.Engine braking is applied with reduced throttle.
First, second, third and fourth gear operation. First to second (1-2), first to third
(1-3), second to third (2-3), second to fourth (2-4), third to fourth (3-4), fourth
to third (4-3), fourth to second (4-2), third to second (3-2), third to first (3-1)
and second to first (2-1), shifts are all available as a function of vehicle speed,throttle position and the time rate of change of the throttle position (forced
downshift). Lockup clutch may be enabled in 3rd and 4th gears depending on
vehicle type. Refer to the owner’ s manual.
Rear band applied only, with inhibited engagement as a function of vehicle
speed, engine speed and throttle position. The inhibitor switch allows the en-gine to start.
Reverse gear operation, with inhibitor engagement as a function of vehicle
speed, engine speed and throttle position. The inhibitor switch enables reverse lamp operation.
Rear band applied only, with inhibited engagement as a function of vehicle
speed, engine speed and throttle position. The transmission output shaft is
locked. The inhibitor switch allows the engine to start.
Table 2.1 - Gear Selections DRIVING MODE SELECTOR
The driving mode selector consists of a mode selection switch and indicator light. The driving mode selector is
located on the centre console. See figure 2,1.
The schedules available to be selected vary with vehicle types. Typically the driver should have the option to select
between ‘NORMAL’ , ‘POWER’ or ‘WINTER’ modes.
When ‘NORMAL’ mode is selected upshifts will occur to maximise fuel economy and the indicator lights remain
extinguished. When ‘POWER’ mode is selected upshifts will occur to give maximum performance and the ‘POWER’
mode indicator light is swi tched on. When ‘WINTER’ mode is selected, starting at second gear is facilitated, the
‘WINTER’ mode indicator light is switched on and the ‘POWER’ mode indicator light is switched off.
Refer to the vehicle owner ’ s manual for specific modes for each vehicle type.
AUTOMATIC TRANSMISSION 5A-39
Primary Regulator Valve
The primary regulator valve (PRV) (refer to figure 3.19) regulates the transmission line pressure (or pump output
pressure). This valve gives either high or low line pressure depending on whether S6 is switched Off or On, When S6
is switched On,S6 pressure is applied to the PRV moving it against spring pressure and opening the line pressure
circuit to the pump suction port resulting in reduced line pressure. Low line pressure is used during light throttle
applications and cruising. Heavy throttle will cause S6 to switch Off and thereby cause high line pressure.
This stepped line pressure control has no detrimental effect on shift feel because all shifting pressures are controlled
by separate band and clutch regulator valves, and the output of S5.
When reverse gear is selected, both the low and high line pressure values are boosted to guard against slippage.
This is achieved by applying reverse oil line pressure to the PRV to assist the spring load. The other end of the valvecontains ports for line pressure feedback and 56 pressure.
The PRV also regulates the supply of oil to the converter via the converter feed port. The cascade effect of the PRV
ensures the first priority of the valve is to maintain line pressure at very low engine speeds. When the engine speed
increases and the pump supplies an excess of oil the PRV moves to uncover the converter feed port thereby pressurising
the converter. If there is an excess of oil for the transmission’s needs then the PRV moves further to allow oil to return
to the suction port.
Figure 3.19 - Primary Regulator Valve
