789B Off-Highway Truck Power Train Caterpillar

Illustration 1	g00123135

Rotation of the pump is counterclockwise when the pump is viewed from the drive end.

Type of pump: Gear

Lubricate the pump with oil before you operate the pump.

Bench test requirements: SAE 10W oil must be stabilized at 52° ± 3°C (125.6° ± 5.4°F) before the test is performed.

(A) Torque converter scavenge section

Minimum output ... 40 L/min (10.6 US gpm)

Test pressure ... 345 kPa (50 psi)

Test speed of pump ... 900 rpm

(B) Torque converter charging section

Minimum output ... 197 L/min (52.0 US gpm)

Test pressure ... 1035 kPa (150 psi)

Test speed of pump ... 900 rpm

(C) Parking brake release section

Minimum output ... 25 L/min (6.6 US gpm)

Test pressure ... 4136 kPa (600 psi)

Test speed of pump ... 900 rpm

(D) Brake cooling section

Minimum output ... 115 L/min (30.4 US gpm)

Test pressure ... 345 kPa (50 psi)

Test speed of pump ... 900 rpm

(1) Torque for the locknut on the pump drive gear ... 110 ± 13 N·m (81.1 ± 9.6 lb ft)

(2) Clearance between a new gear and a new cover ... 0.104 ± 0.043 mm (0.0041 ± 0.0017 inch)

(3) Clearance between a new gear and a new body ... 0.163 ± 0.038 mm (0.0064 ± 0.0015 inch)

(4) Clearance between a new gear and a new body ... 0.081 ± 0.025 mm (0.0032 ± 0.0010 inch)

(5) Dimensions of new shafts and of new pump bodies

Diameter of the drive shafts and diameter of the driven shafts ... 31.742 ± 0.005 mm (1.2497 ± 0.0002 inch)

Diameter of the bores in the pump body ... 31.786 ± 0.008 mm (1.2514 ± 0.0003 inch)

(6) Clearance between a new gear and a new cover ... 0.125 ± 0.038 mm (0.0049 ± 0.0015 inch)