Automatic Transmission/Transaxle
BORG WARNER 66KEY TO COMPONENTS SHOWN ON HYDRAULIC CHARTS
A. Torque converter
B. Front clutch
C. Rear clutch
D. Front servo
E. Rear servo
F. Governor
G. Pump
H. Primary regulator
J. Secondary regulator
K. 2-3 shift valve
L. 1-2 shift valve
M. Servo orifice control valve
N. Manual valve
P. Down-shift valve
Q. Throttle valve
R. Modulator valve
KEY TO HYDRAULIC CHART COLOUR CODE
Red line....................................Pump pressure
Red cross hatch........................To torque converter
Blue line...................................Governor line pressure
Yellow line.................................Throttle valve
Green line..................................Pump Suction
HYDRAULIC OPERATION IN "P" (PARK - Fig. 9).
Coupled to the manual valve operating lever is a linkage incorporating a pawl; movement of this lever to the 'Park' position engages the pawl with the toothed outer surface of the ring gear. so locking the output shaft to transmission case The rear servo is energized in "P" selection but, as both the front and rear clutches are not energized, drive is impossible and the transmission remains inoperative
HYDRAULIC OPERATION IN "R" (REVERSE - Fig. 10)
Throttle pressure applied to spring end of primary regulator valve increases line pressure proportional to engine output. Manual valve directs line pressure through 1-2 shift valve to apply rear servo and through 2-3 shift valve to release front servo and apply rear clutch.
HYDRAULIC OPERATION IN "N" (NEUTRAL - Fig. 11)
With the engine running, the pump supplies fluid to the primary regulator which regulates line pressure.
Spill from the primary regulator supplies the torque converter and lubrication requirements. This supply is regulated by the secondary regulator.
The line pressure supplied to the manual and throttle valves is blocked by a land on the valves so that neither governor, clutches nor servos are energized.
HYDRAULIC OPERATION IN "D" (FIRST GEAR - Fig. 12)
Throttle pressure is applied to spring end of primary regulator valve. When throttle valve is in full throttle position, modulator valve plug applies regulated line pressure to other end of primary regulator valve thereby controlling shift quality.
Manual valve directs line pressure to apply front clutch thereby enabling vehicle to move off in first gear.
Manual valve also directs line pressure to governor feed and to 1-2, 2-3 shift valves for subsequent upwards gear-shifts.
HYDRAULIC OPERATION IN "D" (SECOND GEAR - Fig. 13)
Pressure control by primary regulator valve functions as described in "D" (First gear).
When governor pressure exceeds throttle pressure, 1-2 shift valve moves and directs line pressure to front servo which applies front brake band. Front clutch being applied, transmission operates in second gear.
When down-shift valve is in forced throttle (kick-down) position, forced throttle pressure acts upon 1-2 and 2-3 shift valves thereby delaying up-shifts or, if governor pressure is low, causes a 2-1 down-shift.
HYDRAULIC OPERATION IN "D" (THIRD GEAR - Fig. 14)
Pressure control by primary regulator valve functions as described in "D" (First gear). 2-3 shift occurs early at light throttle or late at full throttle depending upon balance between governor and throttle pressure.
When governor pressure exceeds throttle pressure. 2-3 shift valve directs line pressure to rear clutch and also to release side of front servo via servo orifice control valve.
The timed relationship between rear clutch apply and front servo release is dependent on governor pressure which in turn is controlled by road speed. A high governor pressure closes servo orifice control valve so directing front servo release fluid through a restrictor thereby delaying front servo release in relation to rear clutch apply.
HYDRAULIC OPERATION IN "2" (LOW GEAR - Fig. 15)
Pressure control by primary regulator valve functions as described in "D". (First gear). Front clutch is applied but as engine speed is low, governor pressure causes 1-2 shift valve to remain closed thereby blocking feed from modulator valve.
HYDRAULIC OPERATION IN "2" (SECOND GEAR - Fig. 16)
Front Clutch is still applied and as engine speed increases, governor pressure rises and moves 1-2 shift valve. This allows pressure from manual valve to front servo apply
HYDRAULIC OPERATION IN "1" (LOW GEAR - Fig. 17)
Pressure control by primary regulator valve functions as described in "D" (First gear). Manual valve directs line pressure to front clutch governor feed and 1-2 shift valve. Pressure is also directed to enlarged end of 1-2 shift varve so opposing governor pressure and hydraulically locking the valve. Rear servo is also applied and no up-shift can occur.
HYDRAULIC OPERATION IN "1" (SECOND GEAR - Fig. 18)
When selector lever is moved to position "1" at speed, front servo is released and a down-shift from high to intermediate gear occurs. A further down-shift to low gear occurs when vehicle speed falls sufficiently.