Allison Transmission AT 1545P Service Manual

Copyright © 1996 General Motors Corp. 2–13
DESCRIPTION AND OPERATION
d. Second-Range Operation (Figure 2–3)
(1) The forward and the second clutches are
applied. The second clutch application anchors the
carrier of the front planetary carrier assembly against
rotation. The forward clutch application locks the tur-
bine shaft and main shaft together to rotate as a unit.
The rear sun gear is splined to both the rotating main
shaft and the center ring gear and all three parts rotate
at turbine speed. With the carrier of the front planetary
carrier assembly anchored against rotation, the rotat-
ing center ring gear rotates the center sun gear via the
planetary pinions. This sun gear is splined to the sun
gear shaft assembly to which the front sun gear is also
splined. The rotating front sun gear rotates the front
carrier pinions whose carrier is anchored against rota-
tion by the applied second clutch. In turn, the rotating
front carrier pinions rotate the front ring gear, which,
along with the center carrier, is splined, via the plane-
tary connecting drum and rear carrier assembly, to the
output shaft. Due to this compounding action of the
front and center planetary gear sets, there is an output
speed reduction of 2.25:1.
(2) For AT 1500 Series models, the lockup
clutch does not apply during second range operation.
Figure 2–3. Second Range Power Flow
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V02879
TURBINE SHAFT
SUN GEAR SHAFT
PTO GEAR
FORWARD CLUTCH
THIRD CLUTCH
SECOND CLUTCH
FIRST CLUTCH
FOURTH CLUTCH
✽
TORQUE
CONVERTER
ASSEMBLY
MAIN SHAFT
TORQUE PATH
✽
AT 1500 Series models include a lockup clutch, not active in second range
CLUTCH APPLIED
OUTPUT
SHAFT

Allison Transmission AT 1545P Specifications

General

Brand	Allison Transmission
Model	AT 1545P
Category	Microphone system
Language	English