The transmission portion of the power train enacts an important role in delivering engine power to the driving
wheels. In order to properly maintain and service these units it is important to first understand their function
and how they operate.
The transmission and torque converter function together and operate through a common hydraulic system. To
obtain maximum serviceability they have been designed and built as separate units. It is necessary, however, to
consider both units in the study of their function and operation.
To supplement the text below, and for references use therewith, the following illustrations are provided:
Fig F -- Input and Forward Drive Shaft Group-"F"
Fig. A Front and Rear View, Shaft Identification
Reverse Drive Shaft Group - "R"
Fig. E Transmission Case and Internal Tubing
Fig. H - 2nd and 4th Drive Shaft Group - "A"
Fig. C - Control Cover Assembly
Fig. I - 1st and 3rd Drive Shaft Group - "8"
F i g . D O u t p u t Shaft Group "0"
Fig. J - External Oil Flow-Converter and Trans-
Fig. E - Idler Shaft Group - "I"
HOW THE UNITS OPERATE -
With the engine running, the converter charging pump draws oil from the transmission sump and directs
it through oil filters to the regulating valve located on top of the transmission. From the regulating valve it is
then directed through the control cover on the transmission to the converter and to the transmission clutches.
The pressure regulating valve mounted on the top of the transmission remains closed until required pressure
is delivered to the transmission for actuating the direction and speed clutches. This regulator valve consists of a
hardened valve spool operating in a closely fitted bore. The valve spool is backed up by a spring to hold the valve
spool against its seat until the oil pressure builds up to the specified pressure. The valve spool then moves toward
the spring until a port is exposed along the side of the bore. The oil can then flow through this port into a dis-
tributor which directs the oil into the converter inlet port.
After entering the converter, the oil is directed through the stator support to the converter cavity and exits
between the turbine shaft and converter support. The oil then passes through an oil distributor which directs
the oil our of the converter by way of a down stream regulator valve and then to the oil cooler. After leaving the
cooler the oil is directed through a hose to the lubricating oil inlet on the transmission, then through a series of
tubes to the transmission, bearings, and clutches. The oil then returns to the transmission sump.
A safety valve is built in the transmission control cover and will open to bypass oil only if an excessive
pressure is built up due to a blocked passage.
The rear compartment of the converter unit also houses the converter output shaft. A flexible hose provides
an overflow to the transmission sump.
The three members of the torque converter are composed of a series of blades. The blades are curved in such
a manner as to force the oil to circulate from the impeller to the turbine, through the reaction member again into
the impeller. This circulation causes the turbine to turn in the same direction as the impeller. Oil enters the inner
side of the impeller and exits from the outer side into the outer side of the turbine. It then exits from the inner
side of the turbine and after passing through the reaction member, again enters the inner side of the impeller.
Converter stall is achieved whenever the turbine and output shaft are stationary and the engine is operating
at full power or wide open throttle. CAUTION: Do not maintain "Stall" for more than 30 seconds at a time.
Excessive heat will be generated and may cause converter or transmission seal damage.
In converters equipped with Lock-up clutches, a hydraulic clutch, similar to the transmission clutches is used
to "lock" the engine mechanically to the output shaft This is accomplished by hydraulic pressure actuating the
lock-up clutch which in turn locks the impeller cover to the turbine hub. During lock-up the converter turns at 1
to 1 speed ratio.
The down stream regulator valve on the converter consists of a valve body and regulator spool, The spool
is backed up by a spring to hold the valve until converter oil pressure builds up to specified pressure. The valve
is used to maintain a given converter pressure to insure proper performance under all conditions.
The control valve assembly on the transmission consists of a valve body with selector valve spools connected
to the steering column by exterior linkage. A detent ball and spring in the selector spool provides four positions,
one position for each speed range. A detent ball and spring in the direction spool provides three positions, one
each for forward, neutral, and reverse.
On certain models, this valve also contains a shut-off valve spool operated by an air or hydraulic cylinder
located on the control cover. This valve is connected to the brake system by a hose line. When the wheel brakes
are applied, air or hydraulic fluid enters the valve and overcomes a spring force. This forces the spool to shift
over and block pressure from entering the directional clutches. In this manner a "neutral" is established without
With the engine running and the directional control lever in neutral position, oil pressure is blocked at the con-
trol valve, and the transmission is in neutral. Movement of the forward and reverse spool will direct oil, under pres-
sure, to either the forward or reverse direction clutch as desired, and the opposite one is open to relieve pressure.