2001 DODGE RAM rear diff

DIAGNOSIS AND TESTINGÐREAR SEAL AREA
LEAKS
Since it is sometimes difficult to determine the
source of an oil leak in the rear seal area of the
engine, a more involved inspection is necessary. The
following steps should be followed to help pinpoint
the source of the leak.
If the leakage occurs at the crankshaft rear oil seal
area:
(1) Disconnect the battery.
(2) Raise the vehicle.
(3) Remove torque converter or clutch housing
cover and inspect rear of block for evidence of oil.
Use a black light to check for the oil leak:
(a) Circular spray pattern generally indicates
seal leakage or crankshaft damage.
(b) Where leakage tends to run straight down,
possible causes are a porous block, distributor seal,
camshaft bore cup plugs, oil galley pipe plugs, oil
filter runoff, and main bearing cap to cylinder
block mating surfaces.
(4) If no leaks are detected, pressurized the crank-
case as outlined in (Refer to 9 - ENGINE/LUBRICA-
TION - DIAGNOSIS AND TESTING)
CAUTION: Do not exceed 20.6 kPa (3 psi).
(5) If the leak is not detected, very slowly turn the
crankshaft and watch for leakage. If a leak is
detected between the crankshaft and seal while
slowly turning the crankshaft, it is possible the
crankshaft seal surface is damaged. The seal area on
the crankshaft could have minor nicks or scratches
that can be polished out with emery cloth.
CAUTION: Use extreme caution when crankshaft
polishing is necessary to remove minor nicks or
scratches. The crankshaft seal flange is specially
machined to complement the function of the rear oil
seal.
(6) For bubbles that remain steady with shaft
rotation, no further inspection can be done until dis-
assembled. Refer to the service DiagnosisÐMechani-
cal, under the Oil Leak row, for components
inspections on possible causes and corrections.
(7) After the oil leak root cause and appropriate
corrective action have been identified, (Refer to 9 -
ENGINE/ENGINE BLOCK/CRANKSHAFT OIL
SEAL - REAR - REMOVAL), for proper replacement
procedures.
STANDARD PROCEDUREÐCYLINDER BORE
HONING
Before honing, stuff plenty of clean shop towels
under the bores and over the crankshaft to keep
abrasive materials from entering the crankshaft
area.
(1) Used carefully, the Cylinder Bore Sizing Hone
C-823, equipped with 220 grit stones, is the best tool
for this job. In addition to deglazing, it will reduce
taper and out-of-round, as well as removing light
scuffing, scoring and scratches. Usually, a few strokes
will clean up a bore and maintain the required lim-
its.
CAUTION: DO NOT use rigid type hones to remove
cylinder wall glaze.
(2) Deglazing of the cylinder walls may be done if
the cylinder bore is straight and round. Use a cylin-
der surfacing hone, Honing Tool C-3501, equipped
with 280 grit stones (C-3501-3810). about 20-60
strokes, depending on the bore condition, will be suf-
ficient to provide a satisfactory surface. Using honing
oil C-3501-3880, or a light honing oil, available from
major oil distributors.
CAUTION: DO NOT use engine or transmission oil,
mineral spirits, or kerosene.
(3) Honing should be done by moving the hone up
and down fast enough to get a crosshatch pattern.
The hone marks should INTERSECT at 50É to 60É
for proper seating of rings (Fig. 3).
Fig. 3 Cylinder Bore Crosshatch Pattern
1 - CROSSHATCH PATTERN
2 - INTERSECT ANGLE
9 - 10 ENGINE 3.9LBR/BE
ENGINE 3.9L (Continued)

INSTALLATION
(1) Install the plunger, spring, and plug as shown
in (Fig. 152). Tighten the plug to 80 N´m (60 ft. lbs.)
torque.
(2) Connect the battery negative cables.
(3) Start the engine and verify that it has oil pres-
sure.
OIL PRESSURE SENSOR/
SWITCH
DESCRIPTION
The 3±wire, solid-state oil pressure sensor is
installed into the oil pressure galley on the engine
block. It is located below and to the rear of the
Engine Control Module (ECM) (Fig. 154).
OPERATION
Operation of the oil pressure sensor on the
diesel engine is controlled by the Engine Con-
trol Module (ECM). The Powertrain Control
Module (PCM) does not have any control over
the sensor.The oil pressure sensor uses three circuits. They
are:
²A 5±volt power supply from the ECM
²A sensor ground through the ECM's sensor
return
²A signal to the ECM relating to engine oil pres-
sure
The oil pressure sensor has a 3±wire electrical
function very much like the Manifold Absolute Pres-
sure (MAP) sensor on the gasoline powered engine.
Meaning different pressures relate to different output
voltages.
A 5±volt supply is sent to the sensor from the ECM
to power up the sensor. The sensor returns a voltage
signal back to the ECM relating to engine oil pres-
sure. This signal is then transferred (bussed) to the
instrument panel on the CCD bus circuit to operate
the oil pressure gauge and the check gauges lamp.
Ground for the sensor is provided by the ECM
through a low-noise sensor return.
REMOVAL
(1) Disconnect the battery negative cables.
(2) Disconnect the oil pressure sensor connector
(Fig. 155).
(3) Using a suitable socket, remove the oil pres-
sure sensor from the block (counter-clockwise).
Fig. 154 Oil Pressure Sensor (Engine) Location
1 - ENGINE OIL PRESSURE SENSOR
2 - ELECTRIAL CONNECTOR
3 - ECM
Fig. 155 Oil Pressure Sensor Location
1 - ENGINE OIL PRESSURE SENSOR
2 - ELECTRIAL CONNECTOR
3 - ECM
9 - 298 ENGINE 5.9L DIESELBR/BE
OIL PRESSURE RELIEF VALVE (Continued)

DIMENSIONS FOR DIFFERING WHEELBASES*
WHEELBASE LENGTH
ALENGTH
BLENGTH
C
118 2118.0 3663.6 4185.4
134 2118.0 3994.5 4693.4
138 2626.0 4096.1 4693.4
154 2626.0 4502.5 5201.4
162 2118.0 4705.0 5042.5
*Measurements are in Millimeters (mm).
TORQUE SPECIFICATIONS
DESCRIPTION TORQUE
Cab Chassis adapter nut..... 108N´m(80ft.lbs.)
Front bumper brkt-to-frame nut . 68 N´m (50 ft. lbs.)
Front bumper outer brace bolt . . 68 N´m (50 ft. lbs.)
Rear bumper-to-brace nut..... 40N´m(30ft.lbs.)
Rear bumper brace-to-brkt nut . 101 N´m (75 ft. lbs.)
Rear bumper brkt-to-frame nut......... 101N´m
(75 ft. lbs.)
Skid plate crossmember-to-frame bolt..... 54N´m
(40 ft. lbs.)
Skid plate-to-crossmember bolt . 40 N´m (30 ft. lbs.)
Skid plate-to-trans crossmember bolt...... 54N´m
(40 ft. lbs.)
Spare tire winch bolt......... 27N´m(20ft.lbs.)
Trailer hitch nut............ 108N´m(80ft.lbs.)
CAB CHASSIS ADAPTER
BRACKET
REMOVAL
(1) Remove bolts attaching cab chassis adapter
brackets to frame rail (Fig. 11)
(2) Separate cab chassis adapter brackets from
frame rail
INSTALLATION
(1) Position cab chassis adapter brackets on frame
rail
(2) Install bolts attaching cab chassis adapter
brackets to frame rail.
FRONT TOW HOOK
REMOVAL
Some vehicles are equipped with front tow hooks.
The tow hooks are to be used forEMERGENCYpur-
poses only.(1) Remove the fasteners that attach the tow
hooks to the frame (Fig. 12).
(2) Separate the tow hooks from the frame.
Fig. 11 Cab Chassis Adapter Brackets
1 - ADAPTER BRACKETS
2 - FRAME
Fig. 12 Front Tow Hooks
1 - TOW HOOK
2 - FRAME
BR/BEFRAME & BUMPERS 13 - 9
SPECIFICATIONS (Continued)

(3) Installrearinjection line bundle beginning
with cylinder head (fuel injector) connections, fol-
lowed by injection pump connections. Tighten all fit-
tings finger tight.
(4) Tighten fittings at fuel injector ends for cylin-
ders number 6 and 5 to 38 N´m (28 ft. lbs.) torque.
Do not tighten number 3 line at this time. It
will be tightened during bleeding procedure.
(5) Tighten 3 fittings at fuel injection pump ends
to 24 N´m (18 ft. lbs.) torque.
(6) Installfrontinjection line bundle beginning
with cylinder head (fuel injector) connections, fol-
lowed by injection pump connections. Tighten all fit-
tings finger tight.
(7) Tighten fitting at fuel injector end for cylinder
number 2 to 38 N´m (28 ft. lbs.) torque.Do not
tighten lines number 1 or 4 at this time. They
will be tightened during bleeding procedure.
(8) Tighten remaining 3 fittings at fuel injection
pump ends to 24 N´m (18 ft. lbs.) torque.
(9) Install fuel line support bracket bolts to intake
manifold and tighten to 24 N´m (18 ft. lbs.) torque.
CAUTION: Be sure fuel lines are not contacting
each other or any other component. Noise will
result.
(10) Install engine lifting bracket at rear of intake
manifold. Tighten 2 bolts to 77 N´m (57 ft. lbs.)
torque.
(11) Install cable bracket housing/cable assembly
and tighten 3 mounting bolts to 24 N´m (18 ft. lbs.)
torque.
(12) Clean any old gasket material below and
above intake manifold air heater element block. Also
clean mating areas at intake manifold and air intake
housing.
(13) Using new gaskets, position intake manifold
air heater element block to engine.
(14) Install air intake housing and position ground
cable. Install 4 mounting bolts and tighten to 24 N´m
(18 ft. lbs.) torque.
(15) Install air tube (intake manifold-to-charge air
cooler) (Fig. 41). Tighten clamps to 8 N´m (72 in. lbs.)
torque.
(16) Install engine oil dipstick tube support mount-
ing bolt and tighten to 24 N´m (18 ft. lbs.) torque.
(17) Install engine oil dipstick to engine.
(18) Connect 2 electrical cables to cable mounting
studs.
(19) Connect electrical connector to bottom of
APPS by pushing connector upward until it snaps
into position.
(20) Connect wiring harness (clip) at bottom of
Accelerator Pedal Position Sensor (APPS) mounting
bracket (Fig. 40).(21) Connect front wiring clip (Fig. 41) to cable
bracket housing.
(22) Install cable cover (Fig. 39).
(23) Connect both negative battery cables to both
batteries.
(24) Bleed air from fuel system. Do this at fuel
injector ends of lines. Use cylinders numbers 1, 3 and
4 for bleeding . (Refer to 14 - FUEL SYSTEM/FUEL
DELIVERY - STANDARD PROCEDURE). After
bleeding, tighten fittings to 38 N´m (28 ft. lbs.)
torque.
(25) Check lines/fittings for leaks.
FUEL TANK
DESCRIPTION - DIESEL FUEL TANK
The fuel tank is similar to the tank used with gas-
oline powered models. The tank is equipped with a
separate fuel return line and a different fuel tank
module for diesel powered models. A fuel tank
mounted, electric fuel pump is not used with diesel
powered models. Refer to Fuel Tank Module for addi-
tional information.
For removal and installation procedures, refer to
Fuel Tank - Gasoline Engines.
FUEL TANK MODULE
DESCRIPTION
An electric fuel pump isnot usedin the fuel tank
module for diesel powered engines. Fuel is supplied
by the engine mounted fuel transfer pump and the
fuel injection pump.
The fuel tank module is installed in the top of the
fuel tank (Fig. 48). The fuel tank module (Fig. 48)
contains the following components:
²Fuel reservoir
²A separate in-tank fuel filter
²Rollover valve
²Fuel gauge sending unit (fuel level sensor)
²Fuel supply line connection
²Fuel return line connection
²Auxiliary non-pressurized fuel supply fitting
OPERATION
Refer to Fuel Gauge Sending Unit.
REMOVAL
(1) Drain and remove fuel tank. Refer to Fuel
Tank Removal/Installation.
(2) Thoroughly clean area around tank module at
top of tank.
14 - 78 FUEL DELIVERY - DIESELBR/BE
FUEL LINES (Continued)

Refer to Fuel Transfer Pump Description/Operation
for an operational description of transfer pump.
The fuel transfer (lift) pump is located on left side
of engine and above starter motor (Fig. 53).
An improperly operating fuel transfer pump, a
plugged or dirty fuel filter, or a defective overflow
valve can cause low engine power, excessive white
smoke and/or hard engine starting.
Before performing following tests, inspect fuel sup-
ply and return lines for restrictions, kinks or leaks.
Fuel leaking from pump casing indicates a leaking
pump which must be replaced.
Pressure Test:Because the transfer pump is oper-
ating at two different pressure cycles (engine running
and engine cranking), two different pressure tests
will be performed.
(1) Remove protective cap at inlet test port (Fig.
54). Clean area around cap/fitting before cap
removal.
(2) Remove protective cap at outlet test port (Fig.
55). Clean area around cap/fitting before cap
removal.
(3) Install Special Fuel Pressure Test Gauge 6828
(or equivalent) to fitting at inlet test port (Fig. 54).(4) To prevent engine from starting, remove fuel
system relay (fuel injection pump relay). Relay is
located in Power Distribution Center (PDC). Refer to
label under PDC cover for relay location.
Fig. 53 Fuel Transfer Pump Location
1 - OIL PRESSURE SENSOR
2 - PUMP BRACKET NUTS (3)
3 - SUPPORT BRACKET BOLT
4 - BANJO BOLT (REAR)
5 - FUEL SUPPLY LINE
6 - ELECTRICAL CONNECTOR
7 - BANJO BOLT (FRONT)
8 - FUEL TRANSFER PUMP
Fig. 54 Fuel Pressure Test Port Fitting (Inlet)
1 - FUEL PRESSURE TEST PORT (INLET)
2 - FUEL FILTER/WATER SEPARATOR
Fig. 55 Fuel Pressure Test Port Fitting (Outlet)
1 - FUEL PRESSURE TEST PORT (OUTLET)
BR/BEFUEL DELIVERY - DIESEL 14 - 81
FUEL TRANSFER PUMP (Continued)

DIAGNOSIS AND TESTING - BOOST PRESSURE
Two pressure gauges attached at two different
points are required for this test.(1) Obtain two 6828 fuel pressure test gauges
(equivalent gauges are OK).Gauge Consistency
Test:Connect the gauges together to a common pres-
sure source and verify pressure consistency of both
gauges. Do this consistency test at approximately 206
kPa (30 psi). If pressures are different, they can still
be used for test. Note and record differences in pres-
sures before testing. Make adjustments as necessary.
(2) Remove 3/4º pipe plug fitting at rear of intake
manifold (Fig. 2). Temporarily replace this fitting
with fitting reducer to adapt to pressure gauge.
Note: This pipe plug is located to front of MAP
sensor. Do not remove plug to rear of MAP sen-
sor. This is a COOLANT passage plug.
(3) Loosen hose clamp and disconnect rubber sig-
nal line (Fig. 3) from 1/8º brass fitting at front of tur-
bocharger.
(4) Remove 1/8º brass fitting (Fig. 3) from turbo-
charger. Temporarily replace this fitting with a 1/8º
ªTº fitting to adapt to pressure gauge.
(5) Reattach signal line to temporary ªTº.
(6) Attach first pressure gauge to intake manifold
fitting.
(7) Attach second pressure gauge to ªTº fitting at
turbocharger.
Engine must be at rated RPM and full load for the
test.
If gauge pressure differential is greater than 3 psi
(6 in. Hg), check intercooler and associated piping for
restrictions, plugging or damage.
Maximum pressure at intake manifold (rated rpm
and load) is 36±37 in/hg63 in/hg (17.7±18.2 psi6
1.5 psi).
Wastegate should open at no higher than 38.7
in/hg (19 psi) at wide open throttle, full load. If
wastegate is out of adjustment, a DTC may have
been set. Refer to Wastegate Adjustment in Engines
for adjustment procedures.
Fig. 2 Boost Pressure Test at Intake Manifold
1 - REAR OF INTAKE MANIFOLD
2 - 3/49PIPE PLUG
Fig. 3 Boost Pressure Test at Turbocharger
1 - TURBOCHARGER
2 - 1/89FITTING
3 - SIGNAL LINE
4 - WASTEGATE ACTUATOR
5 - CONTROL ROD
6 - OIL SUPPLY LINE
BR/BEFUEL INJECTION - DIESEL 14 - 89
FUEL INJECTION - DIESEL (Continued)

OPERATION
The Engine Control Module (ECM) operates the 2
heating elements through the 2 intake manifold air
heater relays.
Refer to Powertrain Diagnostic Procedures for an
electrical operation and complete description of the
intake heaters, including pre-heat and post-heat
cycles.
REMOVAL
The relays are located in engine compartment,
bolted to left inner fender below left battery (Fig. 30).
The mounting bracket and both relays are replaced
as an assembly.
(1) Disconnect both negative battery cables at both
batteries.
(2) Disconnect four relay trigger wires at both
relays (Fig. 30). Note position of wiring before remov-
ing.
(3) Lift four rubber shields from all 4 cables (Fig.
30).
(4) Remove four nuts at cable connectors (Fig. 30).
Note position of wiring before removing.
(5) Remove three relay mounting bracket bolts
(Fig. 30) and remove relay assembly.
INSTALLATION
The relays are located in engine compartment,
bolted to left inner fender below left battery (Fig. 30).
(1) Install relay assembly to inner fender. Tighten
mounting bolts to 4.5 N´m (40 in. lbs.) torque.
(2) Connect eight electrical connectors to relays.
(3) Connect battery cables to both batteries.
INTAKE AIR TEMPERATURE
SENSOR
DESCRIPTION - DIESEL
The intake manifold air temperature sensor is
installed into the rear of the intake manifold (Fig.
31) with the sensor element extending into the air
stream.
OPERATION - DIESEL
The IAT provides an input voltage to the Engine
Control Module (ECM) indicating intake manifold air
temperature. The input is used along with inputs
from other sensors for intake air heater element
operation, for engine protection, fuel timing and fuel
control. As the temperature of the air-fuel stream in
the manifold varies, the sensor resistance changes.
This results in a different input voltage to the ECM.
Fig. 30 Intake Manifold Air Heater Relays
1 - BATTERY (LEFT SIDE)
2 - RELAY MOUNTING BOLTS (3)
3 - RELAY TRIGGER WIRES (4)
4 - INTAKE AIR HEATER RELAYS (2)
5 - RUBBER SHIELDS (4)
6 - CABLES TO BATTERY (+)
Fig. 31 Intake Manifold Air Temperature (IAT) Sensor
Location
1 - MANIFOLD AIR PRESSURE (MAP) SENSOR
2 - REAR OF CYLINDER HEAD
3 - IAT SENSOR
4 - ELECTRICAL CONNECTOR
5 - ELECTRICAL CONNECTOR
14 - 102 FUEL INJECTION - DIESELBR/BE
INTAKE AIR HEATER RELAY (Continued)

REMOVAL - DIESEL
The IAT sensor is located in the left/rear side of
the intake manifold (Fig. 32).
The IAT sensor is located in the left/rear side of
the intake manifold (Fig. 32).
(1) Disconnect electrical connector from IAT sensor
(Fig. 32).
(2) Remove IAT sensor from intake manifold (Fig.
33).
(3) Discard sensor o-ring (Fig. 33).
INSTALLATION - DIESEL
The IAT sensor is located in the left/rear side of
the intake manifold (Fig. 32).
(1) Clean sensor mounting hole (Fig. 33) of rust or
contaminants.
(2) Install new o-ring to sensor. Apply clean engine
oil to sensor o-ring and sensor threads.
(3) Install IAT sensor into intake manifold.
Tighten to 14 N´m (10 ft. lbs.) torque.
(4) Connect sensor electrical connector.
MAP SENSOR
DESCRIPTION - DIESEL
The MAP sensor is installed into the rear of the
intake manifold (Fig. 31).
OPERATION - DIESEL
The MAP sensor reacts to air pressure changes in
the intake manifold. It provides an input voltage to
the Engine Control Module (ECM). As pressure
changes, MAP sensor voltage will change. The
change in MAP sensor voltage results in a different
input voltage to the ECM. The ECM uses this input,
along with inputs from other sensors to provide fuel
timing, fuel control and engine protection. Engine
protection is used to derate (drop power off) the
engine if turbocharger pressure becomes to high.
Fig. 32 IAT Sensor
1 - SENSOR MOUNTING HOLES
2 - O-RING
3 - IAT SENSOR
4 - MAP SENSOR
5 - O-RING
Fig. 33 Intake Manifold Air Temperature (IAT) Sensor
Location
1 - MANIFOLD AIR PRESSURE (MAP) SENSOR
2 - REAR OF CYLINDER HEAD
3 - IAT SENSOR
4 - ELECTRICAL CONNECTOR
5 - ELECTRICAL CONNECTOR
BR/BEFUEL INJECTION - DIESEL 14 - 103
INTAKE AIR TEMPERATURE SENSOR (Continued)