Maintenance & Service Manual
R & HR32000 3 & 6 Speed LD
HOW THE UNITS OPERATE
With the engine running, the converter charging pump draws oil from the transmission sump through the removable oil suction screen
and directs it through the pressure regulating valve and oil filter.
The pressure regulating valve maintains pressure to the transmission control cover for actuating the direction and speed clutches,
This requires a small portion of the total volume of oil used in the system. The remaining volume of oil is directed through the torque
converter circuit to the oil cooler and returns to the transmission for positive lubrication, This regulator valve consists of a hardened
valve spool operating in a closely fitted bore, The valve spool is spring loaded to hold the valve in a closed position, When a specific
pressure is achieved, the valve spool works against the spring until a port is exposed along the side of the bore, This sequence of
events provides the proper system pressure.
After entering the converter housing the oil is directed through the stator support to the converter blade cavity and exits in the passage
between the turbine shaft and converter support. The oil then flows out of the converter to the oil cooler, After leaving the cooler, the oil
is directed to a fitting on the transmission. Then through a series of tubes and passages lubricates the transmission bearings and
clutches. The oil then gravity drains to the transmission sump.
The hydraulic torque converter consists basically of three elements and their related parts to multiply engine torque, The engine power
is transmitted from the engine flywheel to the impeller element through the impeller cover, This element is the pump portion of the
hydraulic torque converter and is the primary component which starts the oil flowing to the other components which results in torque
multiplication. This element can be compared to a centrifugal pump in that it picks up fluid at its center and discharges at its outer
The torque converter turbine is mounted opposite the impeller and is connected to the output shaft of the torque converter. This
element receives fluid at its outer diameter and discharges at its center. Fluid directed by the impeller out into the particular design
of blading in the turbine and reaction member is the means by which the hydraulic torque converter multiplies torque.
The reaction member of the torque converter is located between and at the center or inner diameters of the impeller and turbine
elements. Its function is to take the fluid which is exhausting from the inner portion of the turbine and change its direction to allow
correct entry for recirculation into the impeller element.
The torque converter will multiply engine torque to its designed maximum multiplication ratio when the output shaft is at zero RPM,
Therefore, we can say that as the output shaft is decreasing in speed the torque multiplication is increasing.
The shift control valve assembly consists of a valve body with selector valve spools. A detent ball and spring in the selector spool
provides 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.
With the engine running and the directional control lever in neutral position, oil pressure from the regulating valve is blocked at the
control valve, and the transmission is in neutral. Movement of the forward and reverse spool will direct oil, under pressure to either the
forward or reverse direction clutch as desired.