Chevrolet Light Duty Truck 1973, Service Manual

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A U T O M A T IC T R A N S M IS S IO N 7 A -67
L2 RANGE-SECOND GEAR
(Valves in Second Gear Position)
band as it holds the sun gear fixed. Without the band
applied while coasting, the sun gear would overrun the
intermediate roller clutch.
Power Flow
Forward Clutch - On
Low Roller Clutch - Ineffective
Direct Clutch - Off
Front Band - On
Rear Band - Off
Intermediate Clutch - On
Intermediate Roller Clutch - Effective
Detent Solenoid - De-energized
In second gear, the intermediate clutch is applied to
allow the intermediate roller clutch to hold the sun gear
against counterclockwise rotation. Turbine torque,
through the forward clutch, is now applied through the
mainshaft to the rear internal gear in a clockwise
direction.
Clockwise rotation of the rear internal gear turns the
rear pinions clockwise against the stationary sun gear.
This causes the output carrier and output shaft to turn
clockwise in a reduction ratio of approximately 1.5:1.
In second gear, engine braking is provided by the front
Oil Flow
When the selector lever is in L2, intermediate oil from
the manual valve is directed to the:
1. Pressure Boost Valve
2. 2-3 Shift Valve
Intermediate oil at the boost valve will increase line
pressure to 150 psi. This increased intermediate oil
pressure at the 2-3 shift valve will close the 2-3 shift
valve, regardless of car speed.
For engine braking, the front band is applied by
exhausting servo oil at the manual valve. This allows
intermediate clutch oil, acting on the servo piston, to
move the piston and apply the front band. Once the
transmission is in second gear-L2, it cannot upshift to
third gear regardless of vehicle speed.
Summary
The forward and intermediate clutches and front band
are applied. The transmission is in second gear - L2
Range.
LIGHT DUTY TRUCK SERVICE MANUAL