Hydraulic Control Removal

Hydraulic

Control

Removal. The

trans-

(3) From the filter, oil is directed to the

mission hydraulic controls can be removed from

control valves in the top compartment of the

removing

without

the

transmission

case

transmission case. The first valve the oil contacts is

t r a n s m i s s i o n from the tractor.

t h e speed spool selector valve (1). The valve is a

four position spool valve which is positioned by

(1) Remove the seat cushion and backrest

mechanical linkage to direct oil to one of the three

(TM 5-2410-233-20), floor plates (para 2-8a),

f l o o r plate framework and the seat frame (para 2-

speed clutches (No. 3, No. 4, or No. 5). A parallel

9).

passage in the speed selector valve housing directs

t h e oil flow to the pressure control valve housing

(2) Clean the transmission case to remove

a c c u m u l a t i o n s of dirt and grease that could enter

(9).

t h e case when the cover is removed.

( 4 ) The pressure control valve is composed of

two valve systems; the pressure relief valve (7), and

( 3 ) Remove transmission oil filler spout and

top cover from transmission case (para 6-8).

the pressure differential valve (8). These valves act

i n combination to limit the maximum pressure of

(4) Remove spring (4, fig. 6-21)

the system, control the rate of pressure rise in the

( 5 ) Loosen locknut (5) and screw eyebolt (6)

o u t of speed selector valve.

s y s t e m , and insure the proper sequence of clutch

(6) Loosen locknut (13) and screw eyebolt (7)

engagement.

out of directional valve.

(5) The differential valve (8) allows the

selected speed clutch to become engaged before any

(7) Loosen clamp bolt of lever (2) and pull

shaft (3) from case. Remove lever (2).

oil is directed to the directional clutches. This

arrangement provides smooth engagement and

(8) Remove cover at front of transmission

case and slide safety valve (9) out of valve housing

allows most of the load to be taken up by the

t h r o u g h hole in case.

directional clutches (No. 1 or No. 2). The pressure

relief valve (7) maintains the proper pressure in the

(9) Remove bolts (14) holding pressure

control valve housing (15) to safety and directional

system and by-passes the oil to the torque converter

i n l e t relief valve.

v a l v e housing (8), and lift pressure control valve

(6) The safety valve (6) is a spring-loaded

housing from transmission.

s p o o l valve that shifts the selector lever into the

(10) Remove torque converter inlet pressure

relief valve and pry tube 1/16 forward until it

n e u t r a l position whenever the oil pressure drops

c l e a r s valve housing (8).

below 100 psi and remains for approximately 15

( 1 1 ) Disconnect inlet pressure line from filter

seconds. This valve also blocks the oil passage

at transmission case and pry tube (10) forward

l e a d i n g to the directional valve when the selector

u n t i l it clears speed selector valve housing (1).

l e v e r is in neutral.

(7) The directional spool valve (5) is con-

( 1 2 ) Remove bolts holding two valve housings

tained in the same housing (4) as the safety valve.

(1) and (8) to transmission clutch housings.

T h e directional valve is positioned by the control

(13) Remove clip (12) from tube (11), and

linkage to direct oil to one of the directional

slide tube (11) into speed selector valve housing (1)

clutches (No. 1 or No. 2).

u n t i l tube clears housing (8).

(8) The gear selector lever is located at the left

(14) Lift valve housings up to clear tubes

side of the operator's seat. Mechanical linkage

b e l o w them, and remove valve housings from case.

connects the lever to the speed selector spool valve

(15) Replace transmission top cover while

and to the directional spool valve. Speed shifts are

h y d r a u l i c controls are out of transmission.

made by moving the selector lever forward or back-

ward, and direction is selected by moving the

selector lever to the left or right.

6-24