Dodge Ram Truck 1500-2500-3500. Manual — part 1686

TURBINE

As the fluid that was put into motion by the impeller blades strikes the blades of the turbine, some of the energy and
rotational force is transferred into the turbine and the input shaft. This causes both of them (turbine and input shaft)
to rotate in a clockwise direction following the impeller. As the fluid is leaving the trailing edges of the turbine’s
blades it continues in a “hindering” direction back toward the impeller. If the fluid is not redirected before it strikes
the impeller, it will strike the impeller in such a direction that it would tend to slow it down.

STATOR

Torque multiplication is achieved by locking the stator’s over-running clutch to its shaft. Under stall conditions (the
turbine is stationary), the oil leaving the turbine blades strikes the face of the stator blades and tries to rotate them
in a counterclockwise direction. When this happens the over-running clutch of the stator locks and holds the stator
from rotating. With the stator locked, the oil strikes the stator blades and is redirected into a “helping” direction
before it enters the impeller. This circulation of oil from impeller to turbine, turbine to stator, and stator to impeller,
can produce a maximum torque multiplication of about 2.4:1. As the turbine begins to match the speed of the impel-
ler, the fluid that was hitting the stator in such as way as to cause it to lock-up is no longer doing so. In this con-
dition of operation, the stator begins to free wheel and the converter acts as a fluid coupling.

Torque Converter Fluid Operation - Typical

1 - APPLY PRESSURE

3 - RELEASE PRESSURE

2 - THE PISTON MOVES SLIGHTLY FORWARD

4 - THE PISTON MOVES SLIGHTLY REARWARD

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TORQUE CONVERTER CLUTCH (TCC)

In a standard torque converter, the impeller and tur-
bine are rotating at about the same speed and the
stator is freewheeling, providing no torque multiplica-
tion. By applying the turbine’s piston and friction mate-
rial to the front cover, a total converter engagement
can be obtained. The result of this engagement is a
direct 1:1 mechanical link between the engine and the
transmission.

The clutch can be engaged in second, third, fourth,
and fifth (if appicable) gear ranges depending on over-
drive control switch position. If the overdrive control
switch is in the normal ON position, the clutch will
engage after the shift to fourth gear. If the control
switch is in the OFF position, the clutch will engage
after the shift to third gear.

The TCM controls the torque converter by way of
internal logic software. The programming of the soft-
ware provides the TCM with control over the L/R-CC
Solenoid. There are four output logic states that can
be applied as follows:

•

No EMCC

•

Partial EMCC

•

Full EMCC

•

Gradual-to-no EMCC

NO EMCC

Under No EMCC conditions, the L/R Solenoid is OFF. There are several conditions that can result in NO EMCC
operations. No EMCC can be initiated due to a fault in the transmission or because the TCM does not see the need
for EMCC under current driving conditions.

PARTIAL EMCC

Partial EMCC operation modulates the L/R Solenoid (duty cycle) to obtain partial torque converter clutch application.
Partial EMCC operation is maintained until Full EMCC is called for and actuated. During Partial EMCC some slip
does occur. Partial EMCC will usually occur at low speeds, low load and light throttle situations.

FULL EMCC

During Full EMCC operation, the TCM increases the L/R Solenoid duty cycle to full ON after Partial EMCC control
brings the engine speed within the desired slip range of transmission input speed relative to engine rpm.

GRADUAL-TO-NO EMCC

This operation is to soften the change from Full or Partial EMCC to No EMCC. This is done at mid-throttle by
decreasing the L/R Solenoid duty cycle.

REMOVAL

1. Remove transmission and torque converter from vehicle. (Refer to 21 - TRANSMISSION/AUTOMATIC - 45RFE/

545RFE - REMOVAL)

2. Place a suitable drain pan under the converter housing end of the transmission.

CAUTION: Verify that transmission is secure on the lifting device or work surface, the center of gravity of
the transmission will shift when the torque converter is removed creating an unstable condition. The torque
converter is a heavy unit. Use caution when separating the torque converter from the transmission.

3. Pull the torque converter forward until the center hub clears the oil pump seal.

Stator Operation

1 - DIRECTION STATOR WILL FREE WHEEL DUE TO OIL
PUSHING ON BACKSIDE OF VANES
2 - FRONT OF ENGINE
3 - INCREASED ANGLE AS OIL STRIKES VANES
4 - DIRECTION STATOR IS LOCKED UP DUE TO OIL PUSHING
AGAINST STATOR VANES

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4. Separate the torque converter from the transmission.

INSTALLATION

NOTE: Check converter hub and drive flats for sharp edges, burrs, scratches, or nicks. Polish the hub and
flats with 320/400 grit paper or crocus cloth if necessary. Verify that the converter hub o-ring is properly
installed and is free from debris. The hub must be smooth to avoid damaging the pump seal at installation.

1. Lubricate oil pump seal lip with transmission fluid.

2. Place torque converter in position on transmission.

CAUTION: Do not damage oil pump seal or con-
verter hub o-ring while inserting torque converter
into the front of the transmission.

3. Align torque converter to oil pump seal opening.

4. Insert torque converter hub into oil pump.

5. While pushing torque converter inward, rotate con-

verter until converter is fully seated in the oil pump
gears.

6. Check converter seating with a scale (1) and

straightedge (2). Surface of converter lugs should
be at least 13 mm (1/2 in.) to rear of straightedge
when converter is fully seated.

7. If necessary, temporarily secure converter with

C-clamp attached to the converter housing.

8. Install the transmission in the vehicle.

9. Fill the transmission with the recommended fluid.

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 battery terminals. 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.

SENSOR-TRANSMISSION RANGE

DESCRIPTION

The Transmission Range Sensor (TRS) is part of the solenoid module, which is mounted to the top of the valve
body inside the transmission.

The Transmission Range Sensor (TRS) has five switch contact pins that:

•

Determine shift lever position

•

Supply ground to the Starter Relay in Park and Neutral only.

•

Supply +12 V to the backup lamps in Reverse only.

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The TRS also has an integrated temperature sensor (thermistor) that communicates transmission temperature to the
TCM and PCM.

OPERATION

The Transmission Range Sensor (TRS) communicates shift lever position 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.

There are many possible combinations of open and closed switches (codes). Seven of these possible codes are
related to gear position and five are recognized as “between gear” codes. This results in many 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 transmission operation with a
TRS failure.

GEAR

C5

C4

C3

C2

C1

Park

CL

OP

OP

CL

CL

Temp 1

CL

OP

OP

CL

OP

Reverse

OP

OP

OP

CL

OP

Temp 2

OP

OP

CL

CL

OP

Neutral 1

OP

OP

CL

CL

CL

Neutral 2

OP

CL

CL

CL

CL

Temp 3

OP

CL

CL

CL

OP

Drive

OP

CL

CL

OP

OP

Temp 4

OP

CL

OP

OP

OP

Manual 2

CL

CL

OP

OP

OP

Temp 5

CL

OP

OP

OP

OP

Manual 1

CL

OP

CL

OP

OP

ASSEMBLY-TRANSMISSION SOLENOID/TRS

DESCRIPTION

The transmission solenoid/TRS assembly is internal to
the transmission and mounted on the valve body
assembly. The assembly consists of six solenoids that
control hydraulic pressure to the six friction elements
(transmission clutches), and the torque converter
clutch. The pressure control solenoid is located on the
side of the solenoid/TRS assembly. The solenoid/TRS
assembly also contains five pressure switches that
feed information to the TCM.

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