TM-9-2520-234-35

POWER TRAIN ASSEMBLY; ALLISON MODEL XTG411-2A

TECHNICAL MANUAL; FIELD AND DEPOT MAINTENANCE MANUAL

JULY 1962

TM-9-2520-234-35 - Page 229 of 323

PAR 233

TEST AND ADJUSTMENTS

CHAP 5, SEC XXXIV

- Using a 9/16-inch wrench, re-

move six cap screws 24 and lock washers

25.

- Remove saddle cap 28. Re -

move coupling nut 80 (fig. 381, fold-out

10) and remove coupling retainer 79.

- Disengage shaft 39 (fig. 386,

fold-out 15) by sliding it toward the out-

put drive assembly.

- Reinstall the retainer and nut.

Tighten the nut and install cap 28, wash-

ers 25 and cap screws 24. Tighten bolts to

33-40 pound-feet.

(2) Disengage the left-outpu t

drive assembly (fig. 385, fold-out 14). The

left-output assembly is disengaged in the

same manner as described for the right

side in (1), above.

b. Warm Up

—

(1) Check the transmission oi l

level (fig. 366). Add oil as required to ob-

tain the correct oil level for a safe start.

(2) Start the engine (or test stand

motor) and shift the transmission into 4th

gear. Apply the brakes, and allow the

transmission to operate at an input speed

of 1200 to 1500 rpm for 3 to 8 minutes,

until normal operating temperature (ap-

proximately 220 degrees F) is reached.

(3) Shift through all ranges se-

veral times to insure that the hydraulic

system is fully charged. Reduce the input

speed to make shifts from a forward range

to a reverse range, or from reverse range

to a forward range.

(4) Shift the transmission t o

neutral range, apply the brakes, and in-

crease the input speed to 1200-1500 rpm

and maintain for three minutes.

stop

engine, wait twenty minutes, then check

the transmission oil level. Add or drain

the oil until oil level is at the top of the

OPERATING RANGE marking on th e

indicator (fig. 366).

c . Leak Check. During the warm-up

period, inspect the transmission for oil

leaks at split lines and around bolts and

plugs. If leakage is present, check bolts

and plugs for tightness. If leakage con-

tinues,

replace gaskets where required.

Leakage of oil, in many cases, can cause

faulty operation of the transmission.

d . Oil Pressures.

All necessary oil

pressure tests can be made during the

functional tests outlined in e , below, and

in fig. 367.

Fig. 368 illustrates and iden-

tifies the transmission oil pressure check

points.

e. Functional Tests

—

(1) The test data log sheet (fig.

367) can be used as a guide for making the

proper tests, as well as providing spaces to

record actual tests results. In addition,

the normal pressures are included for com-

parison with test results.

(2) In all tests, the transmission

oil must be at normal operating tempera-

ture (approximately 220 degrees F). Con-

nect the pressure gage to the check point

indicated, for the test being made (fig.

369).

(3)

Reduce

the

speed

of

the

transmission input to engine idle speed

before engaging the desired range. Then

slowly increase the speed to the desired

input speed. Record the readings for each

test.

(4) Do not attempt to remove or

install gages while the transmission is

operating.

Reinstall plugs immediately

upon removing the gage.

(5) When making the tests for

steer clutch pressure, move the steer con-

trol from Center to Full steer slowly while

observing the pressure rise. It should rise

to maximum as the control is moved fully

to steer position.

(6) In tests for lockup engage-

ment, increase speed slowly until lockup

apply pressure registers. Record lockup

pressure and input speed. Record gover-

nor pressure at lockup engagement (full

TV).

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