Section III. TRANSMISSION CONTROL VALVE

TM 10-3930-621-34

(3) Record measurement from face of tangs to

housing face.

(4) If measurement is less than 2.968 inches,

remove converter and add shims at converter pilot to

obtain specified dimension.

(5) If measurement is more than 2.982, insert

suitable gasket between converter housing and flywheel

housing to obtain specified dimension.

b. Alinement.

(1) Mount dial indicator as shown in figure 6-10.

(2) Rotate converter and note indicator readings.

Hub runout should not exceed 0.005 inch (0.01 inch TIR).

(3) bend drive plate (3, fig. 6-3) to adjust to

specified dial reading. Do not use shims between plate

and flywheel.

(4) After correct alinement has been attained,

recheck tang depth as described in a above.

Figure 6-10. Checking converter alinement.

Section III. TRANSMISSION CONTROL VALVE

on the inching valve spool. This action allows oil

6-12. Description

pressure in back (of the spool to move it far enough to

a. Pressure Regulator Valve. When oil is being

restrict the flow of oil to the selector valve, thus

pumped to the converter and cooling circuit, it is also

controlling pressure on the clutches. This allows a

being delivered, under full pump pressure, to the

"feathering" effect during inching.

pressure regulator valve in the transmission control

c. Dump Valve The forward and reverse clutch

valve. The regulator controls the oil pressure delivered

supply or dump valve is placed in the circuit to control the

by the pump. The spring is 'calibrated to provide

flow of oil to the selector valve. The valve spool is

between 80 and 100 psi, so that oil under controlled

pressurized by the converter pump through a metering

pressure is ready for delivery to the clutch pack. At the

orifice in a branch circuit from the main supply line.

same time the regulator controls the amount of oil being

Pump pressure at this orifice is reduced to 3 psi,

delivered for clutch cooling. Also, a portion of the cooling

maximum with the engine at full governed speed.

oil is delivered for lubricating the front bearing of the

d. Selector Valve. Oil flowing through the dump

forward drive shaft. Pressure is reduced by forcing the

valve enters the selector valve. With the selector valve

oil through a metering orifice.

plunger in the neutral position, oil is blocked at this point

b. Inching Valve. From the regulator valve, oil

and the truck will not move. When the directional lever is

passes to the inching valve. This valve is a variable

moved to either forward or reverse, the selector valve

regulator, which permits the operator to vary pressure on

plunger opens and ports to either the forward or reverse

the clutch plate from zero to 80 psi. When an "inching"

clutch pistons. Movement of the piston, due to the oil

operation is performed, actuating the inching pedal

pressure in

relieves

spring

pressure

6-13