Dodge Dakota (R1). Manual - part 699

responsive performance, state of the art efficiency fea-
tures and low NVH. Other features include driver
adaptive shifting and three planetary gear sets to pro-
vide wide ratio capability with precise ratio steps for
optimum driveability. The three planetary gear sets
also make available a unique alternate second gear
ratio. The primary 2nd gear ratio fits between 1st and
3rd gears for normal through-gear accelerations. The
alternate second gear ratio (2prime) allows smoother
4-2 kickdowns at high speeds to provide 2nd gear pass-
ing performance over a wider highway cruising range.

The hydraulic portion of the transmission consists

of the transmission fluid, fluid passages, hydraulic
valves, and various line pressure control components.

The primary mechanical components of the trans-

mission consist of the following:

• Three multiple disc input clutches

• Three multiple disc holding clutches

• Five hydraulic accumulators

• Three planetary gear sets

• Dual Stage Hydraulic oil pump

• Valve body

• Solenoid pack
The TCM is the “heart” or “brain” of the electronic

control system and relies on information from vari-
ous direct and indirect inputs (sensors, switches, etc.)
to determine driver demand and vehicle operating
conditions. With this information, the TCM can cal-

culate and perform timely and quality shifts through
various output or control devices (solenoid pack,
transmission control relay, etc.).

TRANSMISSION IDENTIFICATION

Transmission identification numbers are stamped

on the left side of the case just above the oil pan
sealing surface (Fig. 1). Refer to this information
when ordering replacement parts. A label is attached
to the transmission case above the stamped numbers.
The label gives additional information which may
also be necessary for identification purposes.

Fig. 1 Transmission Part And Serial Number

Location

1 - IDENTIFICATION NUMBERS (STAMPED)

21 - 440

AUTOMATIC TRANSMISSION - 45RFE

GEAR RATIOS The 45RFE gear ratios are:

1st . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.00:1
2nd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.67:1
2nd Prime . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.50:1
3rd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.00:1
4th . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.75:1
Reverse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.00:1

OPERATION

The 45RFE offers full electronic control of all auto-

matic up and downshifts, and features real-time
adaptive closed-loop shift and pressure control. Elec-
tronic shift and torque converter clutch controls help
protect the transmission from damage due to high
temperatures, which can occur under severe operat-
ing conditions. By altering shift schedules, line pres-
sure, and converter clutch control, these controls
reduce heat generation and increase transmission
cooling.

To help reduce efficiency-robbing parasitic losses,

the transmission includes a dual-stage transmission
fluid pump with electronic output pressure control.
Under most driving conditions, pump output pres-
sure greatly exceeds that which is needed to keep the
clutches applied. The 45RFE pump-pressure control
system monitors input torque and adjusts the pump
pressure accordingly. The primary stage of the pump
works continuously; the second stage is bypassed
when demand is low. The control system also moni-
tors input and output speed and, if incipient clutch
slip is observed, the pressure control solenoid duty
cycle is varied, increasing pressure in proportion to
demand.

A high-travel torque converter damper assembly

allows earlier torque converter clutch engagement to
reduce slippage. Needle-type thrust bearings reduce
internal friction. The 45RFE is packaged in a one-
piece die-cast aluminum case. To reduce NVH, the
case has high lateral, vertical and torsional stiffness.
It is also designed to maximize the benefit of the
structural dust cover that connects the bottom of the
bell housing to the engine bedplate, enhancing over-
all power train stiffness. Dual filters protect the
pump and other components. A pump return filter is
added to the customary main sump filter. Indepen-
dent lubrication and cooler circuits assure ample
pressure for normal transmission operation even if
the cooler is obstructed or the fluid cannot flow due
to extremely low temperatures.

The hydraulic control system design (without elec-

tronic assist) provides the transmission with PARK,
REVERSE, NEUTRAL, SECOND, and THIRD gears,
based solely on driver shift lever selection. This
design allows the vehicle to be driven (in “limp-in”
mode) in the event of a electronic control system fail-

ure, or a situation that the Transmission Control
Module (TCM) recognizes as potentially damaging to
the transmission.

The TCM also performs certain self-diagnostic

functions and provides comprehensive information
(sensor data, DTC’s, etc.) which is helpful in proper
diagnosis and repair. This information can be viewed
with the DRB scan tool.

DIAGNOSIS AND TESTING - AUTOMATIC
TRANSMISSION

CAUTION: Before attempting any repair on a 45RFE
automatic transmission, check for Diagnostic Trou-
ble Codes with the DRB® scan tool.

Transmission malfunctions may be caused by these

general conditions:

• Poor engine performance

• Improper adjustments

• Hydraulic malfunctions

• Mechanical malfunctions

• Electronic malfunctions
Diagnosis of these problems should always begin

by checking the easily accessible variables: fluid level
and condition, gearshift cable adjustment. Then per-
form a road test to determine if the problem has been
corrected or if more diagnosis is necessary. If the
problem persists after the preliminary tests and cor-
rections are completed, hydraulic pressure checks
should be performed.

DIAGNOSIS AND TESTING - PRELIMINARY
DIAGNOSIS

Two basic procedures are required. One procedure

for vehicles that are drivable and an alternate proce-
dure for disabled vehicles (will not back up or move
forward).

VEHICLE IS DRIVABLE

(1) Check for transmission fault codes using DRB®

scan tool.

(2) Check fluid level and condition.
(3) Adjust gearshift cable if complaint was based

on delayed, erratic, or harsh shifts.

(4) Road test and note how transmission upshifts,

downshifts, and engages.

(5) Perform stall test if complaint is based on slug-

gish acceleration. Or, if abnormal throttle opening is
needed to maintain normal speeds with a properly
tuned engine.

(6) Perform hydraulic pressure test if shift prob-

lems were noted during road test.

(7) Perform air-pressure test to check clutch oper-

ation.

AUTOMATIC TRANSMISSION - 45RFE

21 - 441

AUTOMATIC TRANSMISSION - 45RFE (Continued)

VEHICLE IS DISABLED

(1) Check fluid level and condition.
(2) Check for broken or disconnected gearshift

cable.

(3) Check for cracked, leaking cooler lines, or loose

or missing pressure-port plugs.

(4) Raise and support vehicle on safety stands,

start engine, shift transmission into gear, and note
following:

(a) If propeller shaft turns but wheels do not,

problem is with differential or axle shafts.

(b) If propeller shaft does not turn and transmis-

sion is noisy, stop engine. Remove oil pan, and
check for debris. If pan is clear, remove transmis-
sion and check for damaged driveplate, converter,
oil pump, or input shaft.

sion is not noisy, perform hydraulic-pressure test to
determine if problem is hydraulic or mechanical.

DIAGNOSIS AND TESTING - ROAD TESTING

Before road testing, be sure the fluid level and con-

trol

cable

adjustments

have

been

checked

and

adjusted if necessary. Verify that all diagnostic trou-
ble codes have been resolved.

Observe engine performance during the road test.

A poorly tuned engine will not allow accurate analy-
sis of transmission operation.

Operate the transmission in all gear ranges. Check

for shift variations and engine flare which indicates
slippage. Note if shifts are harsh, spongy, delayed,
early, or if part throttle downshifts are sensitive.

Slippage indicated by engine flare, usually means

clutch, overrunning clutch, or line pressure problems.

A slipping clutch can often be determined by com-

paring which internal units are applied in the vari-
ous gear ranges. The Clutch Application chart
provides a basis for analyzing road test results.

CLUTCH APPLICATION CHART

SLP

L/R

OVERRUNNING

P–PARK

R–REVERSE

N-NEUTRAL

D–OVERDRIVE

FIRST

ON*

SECOND

SECOND PRIME

THIRD

FOURTH

LIMP-IN

2–FIRST

ON*

SECOND

LIMP-IN

1–LOW

*L/R clutch is on only with the output shaft speed below 150 rpm.

DIAGNOSIS AND TESTING - HYDRAULIC
PRESSURE TEST

An accurate tachometer and pressure test gauges

are required. Test Gauge C-3293-SP has a 300 psi
range and is used at all locations where pressures
exceed 100 psi.

Pressure Test Port Locations

Only two pressure ports are supplied on the trans-

mission case. The torque converter clutch apply and
release ports are located on the right side of the
transmission case (Fig. 2).

To determine the line pressure, there are two avail-

able methods. The DRB® scan tool can be used to
read line pressure from the line pressure sensor. The
second method is to install Line Pressure Adapter
8259 (Fig. 4) into the transmission case and then
install the pressure gauge and the original sensor
into the adapter. This will allow a comparison of the
DRB® readings and the gauge reading to determe
the accuracy of the line pressure sensor. The DRB®
line pressure reading should match the gauge read-
ing within ±10 psi.

21 - 442

AUTOMATIC TRANSMISSION - 45RFE

AUTOMATIC TRANSMISSION - 45RFE (Continued)

In order to access any other pressure tap locations,

the transmission oil pan must be removed, the pres-
sure port plugs removed and Valve Body Pressure
Tap Adapter 8258-A (Fig. 5) installed. The extensions
supplied with Adapter 8258-A will allow the installa-
tion of pressure gauges to the valve body. Refer to
(Fig. 3) for correct pressure tap location identifica-
tion.

TEST PROCEDURE

All pressure readings should be taken with the

transmission fluid level full, transmission oil at the
normal operating temperature, and the engine at
1500 rpm. Check the transmission for proper opera-
tion in each gear position that is in question or if a
specific element is in question, check the pressure
readings in at least two gear positions that employ

that element. Refer to the Hydraulic Schematics at
the rear of this section to determine the correct pres-
sures for each element in a given gear position.

Fig. 2 Torque Converter Pressure Locations

1 - TCC RELEASE
2 - TO COOLER
3 - TCC APPLY
4 - FROM COOLER
5 - LINE PRESSURE SENSOR

Fig. 3 Pressure Tap Locations

Fig. 4 Line Pressure Adapter 8259

1 - LINE PRESSURE SENSOR PORT
2 - LINE PRESSURE SENSOR
3 - TOOL 8259
4 - PRESSURE TAP

Fig. 5 Valve Body Pressure Tap Adapter 8258-A

1 - 45RFE TRANSMISSION
2 - TOOL 8258-A

AUTOMATIC TRANSMISSION - 45RFE

21 - 443

AUTOMATIC TRANSMISSION - 45RFE (Continued)

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