PG145 Transmission Caterpillar

Transmission Power Flow

Usage:

Reference: Refer to System Operation , "Hydraulic System Schematic", "Location of Electronic Components for Transmission System", and "Location of Hydraulic Components for Transmission System".

In all gears (forward, neutral, and reverse):

The charge pump supplies main oil pressure that is regulated by the charge pressure relief valve. Main oil pressure is available to the clutch circuit and to the torque converter circuit.
Torque converter inlet relief valve provides a reduction in charge pressure for use in the torque converter.
Oil flows out of the torque converter, through an oil cooler, and returns for use in the transmission lubrication circuit.
The torque converter drives the transmission input shaft.

To determine power flow through the transmission, see the provided illustrations for visual reference. Clutch engagement by gear selection is described in the tables below.

The following illustrations depict the locations of the transmission shafts, clutches, and gears. The images are for illustrative purposes only and have been positioned for clarity.

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Illustration 1	g06089151
(1) Gear and forward-low clutch (2) Gear and reverse clutch (3) Gear and forward-high clutch (4) Gear and clutch 3 (5) Gear (fixed to shaft) (6) Reverse idler gear (7) Idler gear

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Illustration 2	g06089157
(8) Output shaft and gear (9) Gear and clutch 1 (10) Gear and clutch 2 (11) Gear (fixed to shaft) (12) Gear (fixed to shaft)

The following tables indicate which solenoids and clutches are activated for each gear selection.

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Table 1
4 Speed Transmission Clutch and Solenoid Engagement by Gear⁽¹⁾
Gear	Active Clutches and Solenoids
Forward 1	Forward Low	Clutch 1
Forward 2	Forward Low	Clutch 2
Forward 3	Forward Low	Clutch 3
Forward 4	Forward High	Clutch 3
Reverse 1	Reverse	Clutch 1
Reverse 2	Reverse	Clutch 2
Reverse 3	Reverse	Clutch 3

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⁽¹⁾	Four speed models include: 458-3823, 458-3825, and 482-2979 Power Shift Transmission Ar.

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Table 2
6 Speed Transmission Clutch and Solenoid Engagement by Gear⁽¹⁾
Gear	Active Clutches and Solenoids
Forward 1	Forward Low	Clutch 1
Forward 2	Forward High	Clutch 1
Forward 3	Forward Low	Clutch 2
Forward 4	Forward High	Clutch 2
Forward 5	Forward Low	Clutch 3
Forward 6	Forward High	Clutch 3
Reverse 1	Reverse	Clutch 1
Reverse 2	Reverse	Clutch 2
Reverse 3	Reverse	Clutch 3