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RELAY-TRANSMISSION CONTROL
DESCRIPTION
The relay is supplied fused B+ voltage, energized by the TCM, and is used to supply power to the solenoid pack
when the transmission is in normal operating mode.
OPERATION
When the relay is “off”, no power is supplied to the solenoid pack and the transmission is in “limp-in” mode. After a
controller reset, the TCM energizes the relay. Prior to this, the TCM verifies that the contacts are open by checking
for no voltage at the switched batteryterminals. After this is verified, the voltage at the solenoid pack pressure
switches is checked. After the relay is energized, the TCM monitors the terminals to verify that the voltage is greater
than 3 volts.
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SENSOR-TRANSMISSION RANGE
DESCRIPTION
The Transmission Range Sensor (TRS) (2) is mounted
to the top of the valve body inside the transmission
and can only be serviced by removing the valve body
assembly. The electrical connector extends through
the transmission case.
The Transmission Range Sensor (TRS) has four
switch contacts that monitor shift lever position and
send the information to the PCM.
OPERATION
The Transmission Range Sensor (TRS) communicates shift lever position (SLP) to the TCM as a combination of
open and closed switches. Each shift lever position has an assigned combination of switch states (open/closed) that
the TCM receives from four sense circuits. The TCM interprets this information and determines the appropriate
transmission gear position and shift schedule.
Since there are four switches, there are 16 possible combinations of open and closed switches (codes). Seven of
these codes are related to gear position and three are recognized as “between gear” codes. This results in six
codes which should never occur. These are called “invalid” codes. An invalid code will result in a DTC, and the TCM
will then determine the shift lever position based on pressure switch data. This allows reasonably normal transmis-
sion operation with a TRS failure.
TRS SWITCH STATES
SLP T42 T41 T3 T1
PCL CL CL OP
RCL OP OP OP
NCL CL OP CL
DOP OP OP CL
2OP OP CL OP
1CL OP CL CL
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REMOVAL
1. Remove valve body assembly from vehicle. (Refer
to 21 - TRANSMISSION/AUTOMATIC - 42RLE/
VA LV E B O D Y - R E M O VA L )
2. Remove the manual shaft seal (1).
3. Remove manual shaft/TRS retaining screw (1).
4. Slide TRS off of manual valve shaft.
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INSTALLATION
1. Install the TRS (2) to the manual shaft. Make sure
TRS locating pin rests in manual valve bore slot.
2. Install the TRS/manual shaft retaining screw (1)
and torque to 5 Nꞏm (45 in. lbs.) torque.
3. Install the manual shaft seal (1).
4. Install valve body to the transmission. (Refer to 21
- TRANSMISSION//AUTOMATIC - 42RLE/VALVE
BODY - INSTALLATION)
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SENSOR-TRANSMISSION TEMPERATURE
DESCRIPTION
The transmission temperature sensor (2) is located in
the transmission range sensor (1) and communicates
transmission sump temperature to the TCM.
OPERATION
The transmission range sensor (TRS) has an integrated thermistor that theTCM uses to monitor the transmission’s
sump temperature. Since fluid temperature can affect transmission shiftquality and convertor lock up, the TCM
requires this information to determine which shift schedule to operate in. The TCM also monitors this temperature
data so it can energize the vehicle cooling fan(s) when a transmission “overheat” condition exists. If the thermistor
circuit fails, the TCM will revert to calculated oil temperature usage.
CALCULATED TEMPERATURE
A failure in the temperature sensor or circuit will result in calculated temperature being substituted for actual tem-
perature. Calculated temperature is a predicted fluid temperature whichis calculated from a combination of inputs:
Battery (ambient) temperature
Engine coolant temperature
In-gear run time since start-up
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BODY-VALVE
DESCRIPTION
The valve body assembly consists of a cast aluminum
valve body (5), separator plate (4), and transfer plate
(3). The valve body contains valves and check balls
that control fluid delivery to the torque converter
clutch, solenoid/pressure switch assembly, and fric-
tional clutches.
Also mounted to the valve body assembly are the
solenoid/pressure switch assembly and the transmis-
sion range sensor (2).
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The valves contained within the valve body (1) include the following :
Regulator valve (8)
Solenoid switch valve (7)
Manual valve (5)
Converter clutch switch valve (6)
Converter clutch control valve (4)
Torque converter regulator valve (2)
Low/Reverse switch valve (3)
In addition, the valve body also contains the thermal valve, #2, 3, 4 & 5 check balls and the 2/4 accumulator assem-
bly.
OPERATION
NOTE: (Refer to 21 - TRANSMISSION/AUTOMATIC - 42RLE - SCHEMATICS AND DIAGRAMS) for a visual aid
in determining valve location, operation and design.
Valve Body - Exploded
1-VALVEBODY
2 - T / C R E G U L AT O R VA LV E
3-L/RSWITCHVALVE
4 - CONVERTER CLUTCH CONTROL VALVE
5 - MANUAL VALVE
6 - CONVERTER CLUTCH SWITCH VALVE
7 - SOLENOID SWITCH VALVE
8 - REGULATOR VALVE
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THERMAL VALVE
The thermal valve (1) is a bi-metallic shudder valve
that helps control the venting rate of oil pressure in
the underdrive clutch passage during release of the
clutch. When the oil temperature is approximately 20
degrees Fahrenheit or less, the valve is fully open to
assist in venting oil past the U1 orifice (2). At temper-
atures above 20 degrees, the valve starts to close and
becomes fully closed at approximately 140 degrees.
The thermal valve is located in the transfer plate of
the valve body.
REGULATOR VALVE
The regulator valve (9) controls hydraulic pressure in
the transmission. It receives unregulated pressure
from the pump (6), which works against spring tension
(8) to maintain oil at specific pressures. A system of
sleeves and ports allows the regulator valve to work at
one of three predetermined pressure levels. Regulated
oil pressure is also referred to as “line pressure.”
1 - THERMAL VALVE
2 - U1 ORIFICE
3 - NUMBER 2 CHECK BALL
1 - FROM OVERDRIVE CLUTCH CIRCUIT
2 - FROM MANUAL VALVE
3 - HYDRAULIC PRESSURE
4-FILTER
5-PUMPINLET
6 - PUMP OUTLET
7 - OIL PRESSURE REGULATED AT THIS POINT
8 - SPRING TENSION
9 - REGULATOR VALVE
10 - TORQUE CONVERTER CONTROL VALVE