Transmission Pressure Test

TM 10-3930-630-34

(4) Operate truck and transmission until

(c) Install retainer (35) and secure with

transmission oil temperature reaches 120 to 140 F.

screws and lock washers (34).

(48.9 to 60.0C).

(d) Install new packings (36) if they were

b. Pressure Test.

removed.

(1) Remove plug and install a pressure gage

(5) Install forward gear and shaft:

(O to 300 psi) (O to 2067 kPa) in mainline pressure tap

(a) Assemble gear (32) on shaft (25) and

(fig. 12-13).

secure to shaft with retaining ring (26).

(2) Place transmission control in forward

(b) Install shaft into transmission case

position and operate engine at 600 rpm. Mainline

and assemble bearing (31) and retaining rings (29 and

pressure must read 45-70 psi (310.2 to 482.6 kPa).

30).

Reading must be a steady value within the pressure

(c) Install new gasket (28) and retainer

range for all pressure checks.

(27) and secure with screws (22) and lockwashers (23).

(3) Operate engine at 2000 rpm. Mainline

(6) Install new packings (14 and 15) on drum

pressure must read 130 to 150 psi (896.2 kPa).

assembly. Install retainer (11) on the housing. Replace

(4) Place transmission in neutral and remove

bearing (13), if removed and spacer (12).

pressure gage from mainline pressure tap and install

Secure with screws (9) and lock washers (10). Install

gage in converter charge pressure tap (fig. 12-13).

housing (8) on drum assembly turbine shaft. Use care

(5) Place transmission control in forward

so as not to damage collector rings.

position. Operate engine at 600 rpm. Pressure gage

(7) Attach a hoisting chain to the converter

must read 32 to 65 psi (220.6 to 448.1 kPa).

housing and maneuver housing so that turbine shaft will

(6) Operate engine at 2000 rpm. Pressure

be properly engaged as the drum and housing are

gage must read 80 to 105 psi (551.5 to 723.8 kPa).

attached to the transmission case. Install screws (3 and

(7) Place transmission in neutral position.

4) and lock washers (5) and tighten securely.

Remove pressure gage from converter charge pressure

(8) Install new gasket. Align pump index

tap and install gage in forward clutch pressure tap (fig.

marks and install the pump (fig. 12-6) on the turbine

12-13).

shaft. Secure with mounting screws.

(8) Place transmission

control in forward

(9) Position the converter in the pump at the

position. Operate engine at 600 rpm. Pressure gage

back of the transmission, making certain that the

must read 32 to 65 psi (220.6 to 448.1 kPa).

converter hub tangs properly engage the pump.

(9) Operate engine at 2000 rpm. Pressure

(10) Refer to paragraph 12-8 and install control

gage must read 80 to 105 psi (551.5 to 723.8 kPa).

valve. Install elbow (2) and connect tube assembly (1)

(10) Place transmission in neutral position.

to control valve and converter housing.

Remove gage from forward clutch pressure tap and

(11) Install oil level gage (68) and plugs (64, 65,

install gage in reverse clutch pressure tap (fig. 12-13).

66 and 67). Install screen (63), spring (62) and pipe

(11) Place transmission control in forward

plug (61). Install ball (19), spring (18), washer (17), and

position. Operate engine at 600 rpm. Pressure gage

seat (16) in converter housing.

must read 32 to 65 psi (220.6 to 448.1 kPa).

b. Illustration. Refer to paragraph 2-27 and install

(12) Operate engine at 2000 rpm. Pressure

the transmission.

gage must read 80 to 105 psi (551.5 to 723.8 kPa).

(13) Place transmission in neutral. Shut down

12-13. Transmission Pressure Test

engine. Remove gage from transmission. Install floor

a. Preparation.

and toe plates (TM 10-3930-630-12).

(1) Refer to TM 10-3930-630-12 and remove

(14) Remove blocking and lower drive wheels

floor and toe plates. Check transmission oil level. Oil

to the floor.

must be at FULL mark on level gage.

c. Test Results. Check results listed above. If the

(2) Use a suitable hoist or jacks and raise the

transmission does not operate within the listed pressure

front of the truck until both drive wheels clear the floor.

range, repair or replace transmission as detailed above.

Place blocks under truck to hold in this position.

(3) Attach a tachometer to accurately record

engine speed.

12-11