Page 40 - Hydra-matic 6 Speed RWD Technician's Guide (October 2005)

HYDRAULIC CONTROL COMPONENTS

VALVES LOCATED IN THE FLUID PUMP COVER ASSEMBLY
PRESSURE REGULATOR VALVE TRAIN (233-237) Torque Converter Clutch (TCC) Control Valve (227)
Pressure Regulator Valve (233) Controlled by the TCC pressure control (PC) solenoid state, the
Regulates line pressure in relation to vehicle operating condi- TCC control valve directs converter feed limit fluid pressure to
tions (see page 30 on Pressure Regulation). The pressure regula- the release side of the converter clutch and into the cooler fluid
tor valve is biased by PCS line fluid pressure acting on the circuit when in the release position. The TCC control valve
isolator valve, and inner spring (235), pressure regulator valve directs regulated apply fluid to the apply side of the converter
outer spring (234) force and line pressure routed to the end of clutch and converter feed limit fluid directly to the cooler, when
the valve. Line pressure is routed through the valve and into in the applied position. The valve is held in the release position
both the converter feed and decrease fluid circuits. (as shown) by spring force when the TCC PC solenoid is OFF.
With the TCC PC solenoid ON, PCS TCC fluid pressure in-
• A stuck pressure regulator valve could cause high or low
fluid pressure. creases and moves the valve into the apply position against
spring force.
Isolator Valve (236) If stuck, missing or binding, the TCC control valve or spring may
PCS line fluid pressure moves the isolator valve against the cause:
pressure regulator valve inner spring (235). The pressure regu- • Incorrect TCC apply or release
lator valve inner spring then transfers the force from PCS line • Inadequate lubrication and cooling
fluid pressure to the pressure regulator valve. Therefore, line
pressure increases as PCS line fluid pressure increases, which is
proportional to throttle position and engine torque. Converter Feed Limit Valve (220):
When the TCC is released, converter feed fluid passes through
Pressure Relief Ball Valve (225) the converter feed limit valve, moving the valve against spring
The pressure relief ball valve (225) and spring (224) prevent force which limits the pressure of the fluid being directed to the
line pressure from exceeding limits that may damage compo- converter. This limited fluid then enters the converter feed limit
nents within the transmission. Line fluid pressure moves the fluid circuit. It is then directed through the TCC control valve
ball against spring force and exhausts until line pressure de- and into the release side of the converter preventing overheat-
creases sufficiently. ing. When the TCC applies, converter feed limit fluid is directed
• A pressure relief ball not seated or damaged could cause to the TCC control valve and then into the cooler feed circuit.
high or low fluid pressure.
If stuck, missing or binding, the converter feed limit valve or
spring may cause:
• Incorrect TCC apply or release.
• Inadequate lube and cooling.
• Converter over-pressurization.

FLUID
PUMP
PRESSURE RELIEF ASSEMBLY
VALVE
(LOCATED IN PUMP)

CONV FD LIMIT FRONT EXH TCC REL

LUBE
CONV FD LIMIT
CONVERTER FEED LIMIT
LINE TCC CONTROL VALVE COOLER FD
TCC APPLY
PRESSURE REGULATOR VALVE EXH LINE LINE PCS TCC
LINE
REG APP

DECREASE

ISOLATOR

PCS LINE

LINE

Figure 31 SUCTION 31