Operation and maintenance manual

Section 250-0040
SM 2157 8-02
1
BRAKING SYSTEM - Triple Pump
SM - 2763
driving the motors for the disc brake oil cooler and
the motor/triple pump. Oil is supplied via two speed
control valve. Refer to Section 250-0065, TWO
SPEED CONTROL VALVE.
The three separate sections of the triple gear pump are
connected together as one assembly. The front section
consists of driveshaft & gear (10), driven gear (11) and
front pump housing (12). Middle and rear pumps (15)
are coupled to front pump by connecting shaft (13).
OPERATION
Numbers in parentheses refer to Fig. 1. Refer to Fig. 2
for the operation of a typical gear type hydraulic pump.
Refer to Fig. 3 for hydraulic schematic of the triple
pump operation.
As the drive gear rotates, the driven gear rotates in the
DESCRIPTION
Numbers in parentheses refer to Fig. 1. The triple pump
can be identified as item 1 in Section 210-0005,
COOLING SYSTEM SCHEMATIC.
The triple gear pump, mounted off the transmission
power takeoff, provides the following:
a) front section (closest to driveshaft) supplies the
brake circuit as a priority, before augmenting
engine cooling circuit via priority unloader valve.
Refer to Section 250-0075, PRIORITY UNLOADER
VALVE.
b) middle section combines with residual flow from
front section to drive engine cooling fan motor. Low
temperature unloader valve controls flow to fan
motor. Refer to Section 210-0045, LOW
TEMPERATURE UNLOADER VALVE.
c) rear section supplies the brake cooling circuit,
Fig. 1 - Exploded View of Triple Pump
7- Bolt
8- Bolt
9 - Front Cover
10 - Driveshaft & Gear
11 - Driven Gear
12 - Front Pump Housing
13 - Connecting Shaft
14 - 'O' Ring
15 - Rear Pumps
16 - Bolt
1 - Mounting Flange
2 - Seal
3 - Front Seals
4 - Rear Seals
5- Bolt
6 - Washer
2
3
4
6
5
14
15
1
7
8
9
10
11
12
13
16