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Power flow - Drive 2 and manual 2
In Drive 2 and Manual 2, transmission drive is via the input
shaft and forward clutch cylinder. The elements of the trans-
mission function as follows;
• The C2 clutch is applied to drive the forward sun gear.
• The forward sun gear drives the short pinion anti-
clockwise.
• The short pinion drives the long pinion clockwise.
• The B1 band is applied holding the reverse sun gear
stationary therefore the long pinion walks around the
reverse sun gear taking the internal ring gear and output
shaft with it in a clockwise or forward direction.
• The C4 clutch is applied to bypass the 3-4 OWC and
provide engine braking on overrun.
Control
To maintain this arrangement in the steady state sole-
noids and valves are activated as follows;
• Solenoid S1 is switched OFF. S2 is switched ON.
Gear State
Drive 2 and Manual 2
BTRA 4 AUTO TRANSMISSION
REXTON SM - 2004.4
C1
C2
C3
-
X
-
• Drive (line pressure) oil from the manual valve en-gages
the C2 clutch.
• When S1 switches OFF, S1 oil pressure, which is
derived from line 500 pressure, moves the 3-4 shift
valve to the left. At the same time S1 oil is directed to
the 1-2 shift valve which moves the valve to the second
gear position.
• 2nd oil (line pressure) from the 1-2 shift valve is di-
rected to the band apply regulator valve, and to the 2-
3 shift valve.
• The band apply feed regulator valve supplies 2nd oil
(regulated to line pressure multiplied by the valve ratio)
to the Band Apply Feed (BAF) circuit.
• Band apply feed oil is directed to;
- The outer apply area of the front servo
- The 1-2 shift valve to provide an exhaust port when
the transmission is shifted to first gear
- The 3-4 shift valve for use when the transmission is
shifted into fourth gear
• Drive (line pressure) is routed through the 3-4 shift valve
to apply the C4 clutch.
ELEMENTS ENGAGED
C4
B1
B2
X
X
-
3A2-29
1-2
3-4
LU
OWC
OWC
CLUTCH
-
X
-
Y220_3A2400
CHANGED BY
EFFECTIVE DATE
AFFECTED VIN
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