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7-98
GROUP 7-AUTOMATIC TRANSMISSION
the rear clutch drum. Under certain
conditions, the
servo
is released by
directing fluid pressure to the opposite
side of
the
piston,
assisted
by release
spring
force
.
Rear Band and Servo
The rear band fits
around
the plan-
etary
gear drum
.
One end
of
the band
contacts the
end of the
band adjust-
ing screw, and
the other
end
connects
to the rear
servo.
POWER FLOWS
Figure
29 lists
the ratios obtained
throught the
various
power flows
.
Power Row-Neutral
When the transmission
1S
m neu-
tral
(Fig
.
30),
no gears are held or
driven,
and
no power
is
transmitted to
the output
shaft.
Power Row-First Gear,
Manual Low
In first
gear
when the selector lever
is
at
I, the primat.y
sun
gear is driven
and
the pinion
carrier
is held by the
rear band
(Fig.30).
Power
is
trans-
mitted to the primary pinions, the
secondary pinions, and the internal
gear, driving
the
internal
gear
in the
same direction
as
the primary sun
gear. The
secondary sun gear
turns
free in
the reverse
direction
and
has
no
effect on
the gear train
.
Power Flow-First Gear, D
In first
gear at
the D
selector
lever
position, the pinion carrier is held
against
rotation
by
the
one-way
clutch instead
of
by
the
rear band
(Fig.
30).
First
gear in
D is the only
01004-A
FIG. 25- Sectional View of
Typical Torque Converter
gear that uses the one-way clutch.
Power Row-Second Gear
Second gear ratio is obtained by
driving the primary sun gear and
FIG. 26- Planetary Gear Train
REAR CLUTCH DRUM
holding the secondary sun gear (Fig.
30).The primary pinions drive the sec-
ondary pinions, causing them to walk
around the secondary sun gear and to
carry the internal gear and output
shaft around with them.
01006-A
D 113S-C
DRIVE PLATES
01007
-A
FIG. 28- Typical Front Servo
FIG. 27- Front and Rear Clutches
Gear
Selector Lever
Clutch
Band
Gear
Position
AppUed
Applied
Rado
Neutral
N
None
None
-
First
D or 1
Front
Rear<D
2.40:1
Second
D or2
Front
Front
1.47:1
Third
D
Front and Rear
None
1.00:1
Reverse
R
Rear
Rear
2.00:1
CDin
first gear D, the planet carrier is held against rotation by the one-way
clutch.
FIG. 29- Gear Ratios
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