TM-9-2520-215-34

TM 9--2520--215--34

0005 00--7

THEORY OF OPERATION -- CONTINUED

0005 00

HYDRAULIC SYSTEM – Continued

Action of Hydraulic System in Intermediate Range, Lockup Drive, No Steer

NOTE

Refer to Torque Path in Intermediate Range, Lockup Drive, No Steer Schematic View for the

torque path through the transmission.

When in high range, lockup drive, left steer, the system functions as described in this work package except that the

following additional circuits are opened (or closed) to the action of oil flow and pressure:

The range selector valve directs pressure to the intermediate range clutch, through the converter lockup timer

and relay valves, and into the lockup clutch.

When the vehicle is moving forward the output--driven brake coolant and pressure pump operates.

Oil pressure from the range selector valve applies the intermediate range clutch. The output--driven brake coolant

pump draws air when brakes are released. The air is pumped through the output reduction gear assemblies into the

transmission gear compartment. The output--driven pressure pump assists the input--driven pump in supplying oil to

the system.

A throttle controlled lever pivots on a lug at the top of the relay valve cover. When the engine throttle opens, the

plunger compresses a spring against a relay valve. When the vehicle is operating in intermediate or high range, the

relay valve controls the engagement and release of the lockup clutch. Governor pressure is exerted against the end

of the valve. When governor pressure is great enough to overcome the force of the spring, the lockup clutch en-

gages. The position of the throttle will determine the vehicle speed at which lockup occurs. At closed throttle, lockup

will occur at a lower speed; at open throttle, lockup will occur at a higher speed.

In intermediate range, the shift inhibitor will prevent a downshift to low range (or reverse range) until vehicle speed is

reduced to a safe level.

Torque Path in Intermediate Range, Lockup Drive, No Steer Schematic View

LOCKUP CLUTCH APPLIED

INTERMEDIATE RANGE

CLUTCH APPLIED

DIRECTION OF TRAVEL

07i212m

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