Transmission Control Valve assembly

TM 10-3930-634-34

Section

Il.

TRANSMISSION

ASSEMBLY

4-7.

Transmission

Control

Valve

Assem-

4-6.

General

bly

This section contains maintenance data for the trans-

a. General. The control valve consists of a valve

mission assembly including the control valve, front

body with two selector valve spools. A ball detent in

cover and input shaft, rear cover, output shaft and dis-

the selector spool provides three positions, one each

connect assembly, transmission case, parking brake,

for forward, neutral, and reverse. The control valve is

and the four clutches. The transmission is a separate

located on the left side of the transmission housing as

and distinct unit from the torque converter assembly.

shown in figure 4-29.

It is connected by a propeller shaft to the torque con-

verter assembly. Two propeller shafts couple the trans-

b. Removal.

mission to the axles to drive the forklift truck. The

(1) Disconnect control valve linkage (TM 10-

3930-634-12).

torque converter and transmission operate through a

common hydraulic system.

(2) Remove nine screws and washers and carefully

lift off control valve assembly as shown in figure 4-29.

CAUTION

Use caution as the detent springs and balls

may fall out when removing the control

valve.

(3) Remove two detent springs (3, fig 4-30), de-

tent balls (4) and gasket (5).

c. Disassembly.

(1) Remove pressure switch (5, fig. 4-30) and ball

(6).

(2) Remove inching valve (7) from control valve

assembly and remove packing (8). Remove spool (9),

packing (10), oil seal (11), and plug (12) from inching

valve.

(3) Remove nut (13) from inching piston (14).

Remove washer (15), spacer (16), spring (17), and

release valve (18) from inching piston.

(4) Remove spring (19) and spacer (20) from con-

trol valve assembly.

(5) Remove plug (21) and packing (22) from con-

trol valve assembly (33).

(6) Remove seal (23), retaining ring (24), washer

(25), and valve spool (26) from control valve assembly.

(7) Remove seal (27), retaining ring (28), washer

(29), overshift spacer (30), and valve spool (31).

Remove pipe plug (32) from valve spool.

d. Cleaning. Clean all metal parts with cleaning sol-

vent P-D-680. Dry cleaned parts thoroughly.

e. Inspection and Repair.

(1) Inspect valve body for cracks or excessive wear

in spool bores. Replace if defective.

(2) Inspect spools for excessive wear, bent, or

broken condition. Replace if defective.

(3) Discard all seals and preformed packings.

(4) Inspect detent balls for flat or out of round

condition which would not allow proper seating.

Replace defective balls.

(5) Inspect seats in the valve body for cracks or

excessive wear. Replace the valve body if the seats are

defective.

4-12