Transmission Clutch Packs, Gears,and case

TM 10-3930-634-34

4-9. Transmission Clutch Packs, Gears,

and Case.

a. General.

(1) With the engine running and the direction con-

trol lever in neutral position, oil pressure from the

torque converter regulator valve is blocked at the

transmission control valve and the transmission is in

neutral. Movement of the transmission control valve

forward and reverse spool will direct oil under pres-

sure to either the forward or reverse direction clutch

as desired. When either direction clutch is selected,

the opposite clutch is relieved of pressure and vents

back through the transmission control valve direction

selector spool. The same procedure is used in the speed

selector.

(2) The direction or speed clutch assembly con-

sists of a drum with internal splines and a bore to

receive a hydraulically actuated piston. The piston is

oil tight by the use of sealing rings. A steel disc with

external splines is inserted into the drum and rests

against the piston. Next, a bronze disc with internal

splines is inserted. Discs are alternated until the

required total iS achieved. A heavy backup plate is

then inserted and secured with a snap ring. A hub with

outside diameter splines is inserted into the splines of

discs with teeth on the inner diameter. The discs and

hub are free to increase in speed or rotate in the oppo-

site direction as long as no pressure is present in that

specific clutch.

(3) To engage the clutch, the control valve is

placed in the desired position. This allows oil under

pressure to flow from the control valve, through a

tube, to a chosen clutch shaft. This shaft has a drilled

Figure (4-29). Control valve, assembly, removal and installation.

Figure 4-28. Pump shaft, installation.