Allison Transmission AT 1545P Service Manual

2–12 Copyright © 1996 General Motors Corp.
AT 500, 1500 SERIES AUTOMATIC TRANSMISSIONS
c. First-Range Operation (Figure 2 – 2)
(1) The forward and first clutches are ap-
plied. The first clutch application anchors the rear
planetary ring gear against rotation. The forward
clutch application locks the turbine shaft and transmis-
sion main shaft together to rotate as a unit. The rear
sun gear is splined to the main shaft and rotates with it
and, in turn, rotates the rear planetary pinions. The
pinions are part of the carrier assembly which is
splined to the transmission output shaft. With the rear
ring gear held stationary by the applied first clutch and
the rear sun gear rotating the pinions, the rear plane-
tary carrier rotates within the ring gear and drives the
output shaft at a speed reduction of 3.45:1.
(2) For AT 1500 Series models, the lockup
clutch does not apply during first range operation.
Figure 2–2. First Range Power Flow
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V02878
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 first range
CLUTCH APPLIED
OUTPUT
SHAFT

Allison Transmission AT 1545P Specifications

General

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