2–4 Copyright © 1996 General Motors Corp.
AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS
and fourth clutch housing 13 (Foldout 9,A) to the
transmission housing, stopping rotation. Since housing
13 is splined to sun gear shaft 3 (Foldout 10,A), the
shaft is held stationary. This provides a reaction for the
gearing and causes the planetaries to produce third
range.
c. Operation of Second Clutch
(Foldout 9,B)
(1) When the second clutch is released, in-
ternal-splined plates 24 rotate with front planetary car-
rier assembly 8 (Foldout 10,A). The second clutch is
released during all ranges except second.
(2) When hydraulic pressure is directed to
the second clutch piston cavity (rear) of center support
15 (Foldout 9,B), piston 18 compresses plates 23 and
24 against backplate 25. This anchors internal-splined
plates 24 and external-tanged plates 23 to the trans-
mission housing.
(3) The internal-splines of plates 24 are
splined to front planetary carrier assembly 8 (Foldout
10,A), holding the carrier stationary. A compound ar-
rangement in the planetaries produces second range.
2–10. FIRST CLUTCH
a. Description
(Foldout 10,B)
(1) The first clutch includes piston 9, seven
external-tanged clutch plates 4, seven internal-splined
clutch plates 3, and backplate 2.
(2) Piston 9 is in the rear of the transmission
housing. The external tangs of clutch plates 4 engage
the transmission housing and are always stationary. In-
ternal-splined plates 3 engage rear planetary ring gear
5 (Foldout 10,B) or 53 (Foldout 10,A).
(3) Piston 9 (Foldout 10,B) is retained in the
transmission housing by twenty-two springs 8, retainer
7, and snapring 6. Backplate 2 and clutch plates 3 and
4 are retained in the transmission housing by snapring
1.
b. Operation
(Foldout 10,B)
(1) When the first clutch is released, inter-
nal-splined plates 3 and rear planetary ring gear 5 or
53 (Foldout 10,A) rotate. The first clutch is released
during operation in all ranges except neutral, first, and
reverse.
(2) When hydraulic pressure is directed to
the first clutch piston cavity, piston 9 (Foldout 10,B)
compresses clutch plates 3 and 4 against backplate 2.
This locks internal-splined plates 3 to external-tanged
plates 4, which are anchored to the transmission hous-
ing. Plates 3, splined to the rear planetary ring gear,
hold the ring gear stationary.
(3) The stationary ring gear provides a reac-
tion for the planetary gearing to produce either first
range or reverse.
(4) In first range, the driving member is rear
planetary sun gear 31 (Foldout 10,A), which receives
torque through the turbine shaft, the engaged forward
clutch, and the transmission main shaft.
(5) In reverse, the driving member is center
sun gear 19 (Foldout 10,A), which receives torque
through the turbine shaft, the engaged fourth clutch,
and sun gear shaft 3. First range is a simple planetary
action (involving only one planetary). Reverse is a
compound planetary action (involving two planetary
sets).
2–11. PLANETARY GEAR UNIT
a. Description
(Foldout 10,A)
(1) The planetary gear unit includes all of
the gears and shafts in the transmission except the tur-
bine shaft and the rear planetary ring gear.
(2) Three planetary gear sets are included in
the assembly. These are called front planetary, center
planetary, and rear planetary.
(3) The front planetary includes sun gear 6,
carrier assembly 8, and ring gear 18. The center plane-
tary includes sun gear 19, carrier assembly 20, and
ring gear 30. The rear planetary includes sun gear 31,
carrier assembly 36, and ring gear 5 (Foldout 10,B).
(4) The three planetary sets are intercon-
nected by sun gear shaft 3 (Foldout 10,A), main shaft
4, and connecting drum 28. This interconnection of the
planetary input, reaction, and output elements, and
connection of clutches to the shafts and planetary ele-
ments, produces four forward ranges and reverse.
b. Operation.
Refer to Paragraph 2–19.
To Next Page
Loading...
Need help?
General
