cooling DODGE RAM 2003 Service Repair Manual

(1) Disconnect the battery negative cables.
(2) Discharge the A/C system (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - STAN-
DARD PROCEDURE) and remove the A/C condenser
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING/A/C CONDENSER - REMOVAL) (if A/C
equipped).
(3) Remove the transmission auxiliary cooler
(Refer to 7 - COOLING/TRANSMISSION/TRANS
COOLER - REMOVAL).
(4) Remove the boost tubes from the charge air
cooler (Fig. 24).
(5) Remove the charge air cooler bolts. Pivot the
charge air cooler forward and up to remove.
CLEANING
CAUTION: Do not use caustic cleaners to clean the
charge air cooler. Damage to the charge air cooler
will result.
NOTE: If internal debris cannot be removed from
the cooler, the charge air cooler MUST be replaced.(1) If the engine experiences a turbocharger failure
or any other situation where oil or debris get into the
charge air cooler, the charge air cooler must be
cleaned internally.
(2) Position the charge air cooler so the inlet and
outlet tubes are vertical.
(3) Flush the cooler internally with solvent in the
direction opposite of normal air flow.
(4)
Shake the cooler and lightly tap on the end
tanks with a rubber mallet to dislodge trapped debris.
(5) Continue flushing until all debris or oil are
removed.
(6) Rinse the cooler with hot soapy water to
remove any remaining solvent.
(7) Rinse thoroughly with clean water and blow
dry with compressed air.
INSPECTION
Visually inspect the charge air cooler for cracks,
holes, or damage. Inspect the tubes, fins, and welds
for tears, breaks, or other damage. Replace the
charge air cooler if damage is found.
Pressure test the charge air cooler, using Charge
Air Cooler Tester Kit #3824556. This kit is available
through CumminstService Products. Instructions
are provided with the kit.
INSTALLATION
(1) Position the charge air cooler. Install the bolts
and tighten to 2 N´m (17 in. lbs.) torque.
(2) Install the air intake system tubes to the
charge air cooler. With the clamps in position, tighten
the clamps to 11 N´m (95 in. lbs.) torque.
(3) Install the transmission auxiliary cooler (if
equipped) (Refer to 7 - COOLING/TRANSMISSION/
TRANS COOLER - INSTALLATION).
(4)
Install the A/C condenser (if A/C equipped) (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMB-
ING/A/C CONDENSER - INSTALLATION). Recharge
A/C system (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - STANDARD PROCEDURE).
(5) Connect the battery negative cables.
(6) Start engine and check for boost system leaks.
Fig. 24 Air Intake System Tubes
1 - BOLT
2 - CHARGE AIR COOLER
3 - CLAMP
4 - BOOST TUBE
11 - 16 EXHAUST SYSTEMDR
CHARGE AIR COOLER AND PLUMBING (Continued)

STANDARD PROCEDURE - HYDROFORM
FENDER RAIL REPAIR
SAFETY PRECAUTIONS AND WARNINGS
WARNING: USE EYE PROTECTION WHEN GRIND-
ING OR WELDING METAL, SERIOUS EYE INJURY
CAN RESULT.
²BEFORE PROCEEDING WITH FRAME REPAIR
INVOLVING GRINDING OR WELDING, VERIFY THAT
VEHICLE FUEL SYSTEM IS NOT LEAKING OR IN
CONTACT WITH REPAIR AREA, PERSONAL INJURY
CAN RESULT.
²DO NOT ALLOW OPEN FLAME OR HEAT AND
METAL SPATTER FROM ARC WELDING, TO CON-
TACT PLASTIC BODY PANELS. FIRE OR EXPLO-
SION CAN RESULT.
²WHEN WELDED FRAME COMPONENTS ARE
REPLACED, ENSURE COMPLETE PENETRATION
WELD IS ACHIEVED DURING INSTALLATION. IF
NOT, DANGEROUS OPERATING CONDITIONS CAN
RESULT.
²STAND CLEAR OF CABLES OR CHAINS ON
PULLING EQUIPMENT DURING FRAME STRAIGHT-
ENING OPERATIONS, PERSONAL INJURY CAN
RESULT.
²DO NOT VENTURE UNDER A HOISTED VEHI-
CLE THAT IS NOT SUPPORTED ON SAFETY
STANDS, PERSONAL INJURY CAN RESULT.
CAUTION: Do not reuse damaged fasteners, quality
of repair would be suspect. Failure to use only pro-
duction fasteners or fasteners of equivalent hard-
ness can result in loosening or failure. Do not drill
holes in top or bottom frame rail flanges, frame rail
failure can result. When using heat to straighten
frame components do not exceed 566ÉC (1050ÉF),
metal fatigue can result.
CAUTION: This repair procedure assumes damage
to the right or left hydroform fender rail (Fig. 19).
Prior to any repairs, the vehicle must be mounted
on the appropriate frame repair equipment (ªframe
rackº), checked with three dimensional measuring
equipment, and necessary pull corrections made. If
damage exists in the hydroform fender rail, or cab
beyond the area covered by this service procedure
after dimensional corrections are made, the hydro-
form must be replaced in its entirety. Refer to 23 -
BODY/BODY STRUCTURE/WELD LOCATIONS -
SPECIFICATIONS, when replacing the entire hydro-
form.(1) Disconnect and isolate the battery negative
cable.
(2) Remove the front wheelhouse splash shield.
(Refer to 23 - BODY/EXTERIOR/FRONT WHEEL-
HOUSE SPLASH SHIELD - REMOVAL)
(3) Remove the fender. (Refer to 23 - BODY/EXTE-
RIOR/FRONT FENDER - REMOVAL)
(4) Remove the A/C condenser, if required. (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMB-
ING/A/C CONDENSER - REMOVAL)
(5) Remove the A/C lines, if required. Refer to the
Heating and Air Conditioning section of the manual
for recommended procedures.
(6) Remove the radiator assembly. (Refer to 7 -
COOLING/ENGINE/RADIATOR - REMOVAL)
(7) Remove the air cleaner and support bracket, if
required. (Refer to 9 - ENGINE/AIR INTAKE SYS-
TEM/AIR CLEANER ELEMENT - REMOVAL)
(8) Remove the integrated power module. (Refer to
8 - ELECTRICAL/POWER DISTRIBUTION/INTE-
GRATED POWER MODULE - REMOVAL)
(9) Remove the bolts and position aside the wire
harness and grounds, if required.
(10) Remove the upper radiator crossmember.
(Refer to 23 - BODY/EXTERIOR/UPPER RADIATOR
CROSSMEMBER - REMOVAL)
(11) Remove the headlamp unit. (Refer to 8 -
ELECTRICAL/LAMPS/LIGHTING - EXTERIOR/
HEADLAMP UNIT - REMOVAL)
(12) Remove the front cab mount to the Front End
Sheet Metal bracket (FESM) bolt.
(13) Remove the bolts attaching the lower radiator
crossmember to the hydroform fender rail. (Fig. 19)
CAUTION: Do not use any flame or plasma cutting
equipment to cut the frame in this procedure. The
inaccurate and high temperatures achieved during
flame or plasma cutting will change the metal char-
acteristics and may weaken the frame and/or repair
location.
(14) Using a reciprocating saw or equivalent, cut
the fender rail and shotgun at a straight and square
section of the hydroform and remove.
(15) Smooth and square the cut edges.
(16) Using the damaged structure as a reference
cut the service part at the same location as the first
cut. Smooth and square the cut edges.
NOTE: The repair structure should butt up to the
remaining structure and provide the same overall
vehicle geometry.
13 - 12 FRAMES & BUMPERSDR
FRAME (Continued)

(26) Install the front cab mount bolt if previously
removed and tighten to 81 N´m (60 ft. lbs.).
(27) Install the lower radiator crossmember bolts
and tighten to 28 N´m (21 ft. lbs.).
(28) Install the headlamp unit. (Refer to 8 - ELEC-
TRICAL/LAMPS/LIGHTING - EXTERIOR/HEAD-
LAMP UNIT - INSTALLATION)
(29) Install the upper radiator crossmember. (Refer
to 23 - BODY/EXTERIOR/UPPER RADIATOR
CROSSMEMBER - INSTALLATION)
(30) Install the wire harness and ground if previ-
ously removed and install the bolts.
(31) Install the integrated power module, if previ-
ously removed. (Refer to 8 - ELECTRICAL/POWER
DISTRIBUTION/INTEGRATED POWER MODULE -
INSTALLATION)
(32) Install the air cleaner bracket and air cleaner,
if previously removed. (Refer to 9 - ENGINE/AIR
INTAKE SYSTEM/AIR CLEANER ELEMENT -
INSTALLATION)(33) Install the radiator assembly. (Refer to 7 -
COOLING/ENGINE/RADIATOR - INSTALLATION)
(34) Install the A/C lines, if previously removed.
Refer to the Heating and Air Conditioning section of
the manual for the recommended procedures.
(35) Install the A/C condenser, if previously
removed. (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING/A/C CONDENSER - INSTAL-
LATION)
(36) Install the fender. (Refer to 23 - BODY/EXTE-
RIOR/FRONT FENDER - INSTALLATION)
(37) Install the front wheelhouse splash shield.
(Refer to 23 - BODY/EXTERIOR/FRONT WHEEL-
HOUSE SPLASH SHIELD - INSTALLATION)
(38) Reconnect the battery ground.
Fig. 20 ENGINE COMPARTMENT/FRONT STRUCTURE
13 - 14 FRAMES & BUMPERSDR
FRAME (Continued)

pump. The Fuel Pump/Gear Pump is a low-pressure
pump and produce pressures ranging from 551.5 kpa
(80 psi) to 1241 kpa (180) psi. Fuel then enters the
fuel injection pump. Low pressure fuel is then sup-
plied to the FAC (Fuel Control Actuator).
The FAC is an electronically controlled solenoid
valve. The ECM controls the amount of fuel that
enters the high-pressure pumping chambers by open-
ing and closing the FAC based on a demanded fuel
pressure. The FPS (Fuel Pressure Sensor) on the fuel
rail provides the actual fuel pressure. When the
actuator is opened, the maximum amount of fuel is
being supplied to the fuel injection pump. Any fuel
that does not enter the injection pump is directed to
the overflow valve. The overflow valve regulates how
much excess fuel is used for lubrication of the pump
and how much is returned to the tank through the
drain manifold.
Fuel entering the injection pump is pressurized to
between 300 - 1600 bar by three radial pumping
chambers. The pressurized fuel is then supplied to
the fuel rail.
DIAGNOSIS AND TESTING - FUEL INJECTION
PUMP TIMING
With the Bosch injection pump, there are no
mechanical adjustments needed or necessary to
accomplish fuel injection timing. All timing and fuel
adjustments are electrically made by the engine
mounted Engine Control Module (ECM).
REMOVAL
CAUTION: Cleanliness cannot be overemphasized
when handling or replacing diesel fuel system com-
ponents. This especially includes the fuel injectors,
high-pressure fuel lines and fuel injection pump.
Very tight tolerances are used with these parts. Dirt
contamination could cause rapid part wear and pos-
sible plugging of fuel injector nozzle tip holes. This
in turn could lead to possible engine misfire.
Always wash/clean any fuel system component
thoroughly before disassembly and then air dry.
Cap or cover any open part after disassembly.
Before assembly, examine each part for dirt, grease
or other contaminants and clean if necessary. When
installing new parts, lubricate them with clean
engine oil or clean diesel fuel only.
(1) Disconnect both negative battery cables at both
batteries. Cover and isolate ends of both cables.
(2) Remove intake manifold air intake tube (above
injection pump) and its rubber connector hose (Fig.
8).
(3) The Engine Control Module (ECM) is mounted
to left side of engine (Fig. 9). Remove 5 ECM mount-ing bolts and position ECM for injection pump
removal.Do not disconnect wiring connectors
from ECM.
(4) Remove cooling fan shroud.
(5) Remove cooling fan assembly.
(6) Remove accessory drive belt.
(7) Thoroughly clean the rear of injection pump,
and attachment points for its 3 fuel lines (Fig. 10).
Also clean the opposite ends of these same 3 lines at
their attachment points.
(8) Disconnect Fuel Control Actuator (FCA) electri-
cal connector at rear of injection pump (Fig. 11).
(9) Remove fuel line (injection pump-to-overflow
valve).
(10) Remove fuel line (injection pump-to-fuel rail).
(11) Remove fuel line (injection pump-to-fuel filter
housing).
(12) Remove fuel pump drive gear access cover
(plate) with a 1/2 inch drive ratchet. Plate is
threaded to timing gear cover (Fig. 12).
(13) Remove fuel pump drive gear mounting nut
and washer.
(14) Attach C3428B, or L4407A (or equivalent)
gear puller (Fig. 13) to pump drive gear with 2 bolts,
and separate gear from pump (a keyway is not used
on this particular injection pump). Leave drive gear
hanging loose within timing gear cover.
(15) Remove 3 injection pump mounting nuts (Fig.
14), and remove pump from engine.
Fig. 8 INTAKE TUBE AND CONNECTING HOSE
1 - MANIFOLD ABOVE HEATERS
2 - RUBBER CONNECTING HOSE
3 - METAL INTAKE TUBE
4 - CLAMPS (2)
DRFUEL DELIVERY - DIESEL 14 - 65
FUEL INJECTION PUMP (Continued)

(4) Apply clean engine oilto injection pump
o-ring only.
The machined tapers on both injection pump
shaft and injection pump gear must be abso-
lutely dry, clean and free of any dirt or oil film.
This will ensure proper gear-to-shaft tighten-
ing.
(5) Clean pump gear and pump shaft at machined
tapers with an evaporative type cleaner such as
brake cleaner.
(6) Position injection pump to mounting flange on
gear cover while aligning injection pump shaft
through back of injection pump gear.
(7) After pump is positioned flat to mounting
flange, install 3 pump mounting nuts and tighten
finger tight only.Do not attempt a final tightening
at this time.Do not attempt to tighten (pull)
pump to gear cover using mounting nuts. Dam-
age to pump or gear cover may occur. The
pump must be positioned flat to its mounting
flange before attempting to tighten 3 mounting
nuts.
(8) To prevent damage or cracking of components,
install and tighten nuts in the following sequence:
(a) Install injection pump shaft washer and nut
to pump shaft. Tighten nutfinger tight only.
(b) Do preliminary (light) tightening of injection
pump shaft nut.
(c) Tighten 3 injection pump mounting nuts to 8
N´m (70.8 in. lbs.).
(d) Do a final tightening of pump shaft nut to
105 N´m (77 ft. lbs.).
(9) Install drive gear access cover (plate) using a
1/2 inch drive ratchet. Plate is threaded to timing
gear cover.
(10) Install Engine Control Module (ECM) to left
side of engine.
(11) Install fuel line (injection pump-to-overflow
valve). Tighten bolts to 24 N´m (17 ft. lbs.) torque.
(12) Install fuel line (injection pump-to-fuel rail).
Tighten to 24 N´m (17 ft. lbs.) torque.
(13) Install fuel line (injection pump-to-fuel filter
housing). Tighten to 24 N´m (17 ft. lbs.) torque.
(14) Connect Fuel Control Actuator (FCA) electri-
cal connector to rear of injection pump.
(15) Install intake manifold air intake tube (above
injection pump). Tighten clamps.
(16) Install accessory drive belt.
(17) Install cooling fan shroud.
(18) Install cooling fan assembly.
(19) Connect both negative battery cables to both
batteries.
(20) Check system for fuel or engine oil leaks.FUEL LEVEL SENDING UNIT /
SENSOR
DESCRIPTION
The fuel gauge sending unit (fuel level sensor) is
attached to the side of the fuel tank module. The
sending unit consists of a float, an arm, and a vari-
able resistor track (card).
OPERATION
The fuel tank module on diesel powered models
has 3 different circuits (wires). Two of these circuits
are used at the fuel gauge sending unit for fuel
gauge operation. The other wire is used for a ground.
The diesel engine does not have a fuel tank module
mounted electric fuel pump. The electric fuel pump
(fuel transfer pump) is mounted to the engine.
For Fuel Gauge Operation:A constant input
voltage source of about 12 volts (battery voltage) is
supplied to the resistor track on the fuel gauge send-
ing unit. This is fed directly from the Powertrain
Control Module (PCM).NOTE: For diagnostic pur-
poses, this 12V power source can only be veri-
fied with the circuit opened (fuel tank module
electrical connector unplugged). With the con-
nectors plugged, output voltages will vary from
about .6 volts at FULL, to about 7.0 volts at
EMPTY.The resistor track is used to vary the volt-
age (resistance) depending on fuel tank float level. As
fuel level increases, the float and arm move up,
which decreases voltage. As fuel level decreases, the
float and arm move down, which increases voltage.
The varied voltage signal is returned back to the
ECM through the sensor return circuit.
Both of the electrical circuits between the fuel
gauge sending unit and the ECM are hard-wired (not
multi-plexed). After the voltage signal is sent from
the resistor track, and back to the ECM, the ECM
will interpret the resistance (voltage) data and send
a message across the multi-plex bus circuits to the
instrument panel cluster. Here it is translated into
the appropriate fuel gauge level reading. Refer to
Instrument Panel for additional information.
REMOVAL
REMOVAL/INSTALLATION
For diesel removal and installation procedures,
refer to the gas section of Fuel System/Fuel Delivery.
See Fuel Level Sending Unit/Sensor Removal/Instal-
lation.
14 - 68 FUEL DELIVERY - DIESELDR
FUEL INJECTION PUMP (Continued)

INSTALLATION
INSTALLATION - GAS
(1) Align the pump with the mounting holes in the
left cylinder head.
(2) Install 3 pump mounting bolts through the pul-
ley access holes. Tighten the bolts to 28 N´m (21 ft.
lbs.).
(3) Reconnect the pressure line and return hose to
the pump and reservoir. Tighten the pressure line to
37 N´m (27 ft. lbs.).
(4) Install the serpentine drive belt, (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(5) Fill the power steering pump, (Refer to 19 -
STEERING/PUMP - STANDARD PROCEDURE).
INSTALLATION - DIESEL
(1) Set the power steering pump in place in the
engine compartment from the top (Fig. 3).
(2) Install the inner cooler tube.
(3) Tighten the inner cooler tube clamp at the
radiator support side.
(4) Install the 6 intake plenum bolts (Fig. 3).
(5) Tighten the inner cooler tube clamp at the
intake plenum.
(6) Install 3 pump mounting bolts through the pul-
ley access holes. Tighten the bolts to 28 N´m (21 ft.
lbs.).
(7) Tighten the pump bracket to the block.
(8) Reconnect the pressure line and return hose to
the pump and reservoir. Tighten the pressure line to
37 N´m (27 ft. lbs.).
(9) Install the serpentine drive belt, (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(10) Fill the power steering pump, (Refer to 19 -
STEERING/PUMP - STANDARD PROCEDURE).
SPECIFICATIONS
TORQUE CHART
TORQUE SPECIFICATIONS
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Power Steering Pressure
Switch10 Ð 80
Power Steering Line
Pressure Line32 23 Ð
Power Steering Line
Return Line71 52 Ð
Power Steering Line
Pressure Line To Pump37 27 Ð
Power Steering Pump
Mounting Bolts28 27 Ð
Power Steering Pump
Reservoir Bolts75Ð
Power Steering Pump
Bracket Bolts75Ð
DRPUMP 19 - 41
PUMP (Continued)

INSTALLATION
CAUTION: Do not reuse the old power steering
pump pulley it is not intended for reuse. A new pul-
ley must be installed if removed.
(1) Replace the pulley if it's bent, cracked, or loose.
(2) Install the pulley on the pump with an appro-
priate power steering pulley installation tool (Fig. 11)
making sure it is flush with the end of the shaft.
Ensure the tool and pulley remain aligned with the
pump shaft.
(3) Install the power steering pump assembly,
(Refer to 19 - STEERING/PUMP - INSTALLATION).
(4) Run engine until warm (5 min.) and note any
belt chirp. If chirp exists, move pulley outwardapproximately 0.5 mm (0.020 in.). If noise increases,
press on 1.0 mm (0.040 in.).Be careful that pulley
does not contact mounting bolts.
RESERVOIR
REMOVAL
(1) Drain and siphon the power steering fluid from
the reservoir.
(2) Remove the serpentine belt.
(3) Remove the power steering pump (Refer to 19 -
STEERING/PUMP - REMOVAL).
(4) Remove the reservoir mounting bolts.
(5) Remove the reservoir.
(6) Remove the rear bracket to the pump mounting
bolts.
INSTALLATION
(1) Install the reservoir bracket to the pump hous-
ing.Do not reuse the o-rings (install new
o-rings).Tighten bolts to 7 N´m (5 ft. lbs.).
NOTE: Ensure the reservoir is fully seated onto the
pump.
(2) Install the reservoir to the bracket/pump body.
(3) Install the reservoir mounting bolts. Tighten
bolts to 7 N´m (5 ft. lbs.).
(4) Install the power steering pump (Refer to 19 -
STEERING/PUMP - INSTALLATION).
(5) Install the serpentine drive belt, (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(6) Fill the power steering pump, (Refer to 19 -
STEERING/PUMP - STANDARD PROCEDURE).
Fig. 11 PULLEY INSTALLATION
1 - POWER STEERING PUMP
2 - PULLEY
3 - POWER STEERING PUMP PULLEY INSTALLATION TOOL
19 - 46 PUMPDR
PULLEY (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
BUZZING NOISE 1. Fluid Level Low 1. Add fluid and check for leaks.
2. Shift Cable Mis-assembled. 2. Route cable away from engine and bell
housing.
3. Valve Body Mis-assembled. 3. Remove, disassemble, inspect valve
body. Reassemble correctly if necessary.
Replace assembly if valves or springs are
damaged. Check for loose bolts or screws.
4. Pump Passages Leaking. 4. Check pump for porous casting, scores
on mating surfaces and excess rotor
clearance. Repair as required. Loose pump
bolts.
5. Cooling System Cooler Plugged. 5. Replace cooler.
6. Overrunning Clutch Damaged. 6. Replace clutch.
SLIPS IN REVERSE ONLY 1. Fluid Level Low. 1. Add fluid and check for leaks.
2. Gearshift Linkage Mis-adjusted. 2. Adjust linkage.
3. Rear Band Mis-adjusted. 3. Adjust band.
4. Rear Band Worn. 4. Replace as required.
5. Overdrive Direct Clutch Worn. 5. Disassemble overdrive. Repair as
needed.
6. Hydraulic Pressure Too Low. 6. Perform hydraulic pressure tests to
determine cause.
7. Rear Servo Leaking. 7. Air pressure check clutch-servo operation
and repair as required.
8. Band Linkage Binding. 8. Inspect and repair as required.
SLIPS IN FORWARD
DRIVE RANGES1. Fluid Level Low. 1. Add fluid and check for leaks.
2. Fluid Foaming. 2. Check for high oil level, bad pump
gasket or seals, dirt between pump halves
and loose pump bolts. Replace pump if
necessary.
3. Throttle Linkage Mis-adjusted. 3. Adjust linkage.
4. Gearshift Linkage Mis-adjusted. 4. Adjust linkage.
5. Rear Clutch Worn. 5. Inspect and replace as needed.
6. Low Hydraulic Pressure Due to
Worn Pump, Incorrect Control
Pressure Adjustments, Valve Body
Warpage or Malfunction, Sticking,
Leaking Seal Rings, Clutch Seals
Leaking, Servo Leaks, Clogged Filter
or Cooler Lines.6. Perform hydraulic and air pressure tests
to determine cause.
7. Rear Clutch Malfunction, Leaking
Seals or Worn Plates.7. Air pressure check clutch-servo operation
and repair as required.
8. Overrunning Clutch Worn, Not
Holding (Slips in 1 Only).8. Replace Clutch.
SLIPS IN LOW GEAR9D9
ONLY, BUT NOT IN
MANUAL 1 POSITIONOverrunning Clutch Faulty. Replace overrunning clutch.
DRAUTOMATIC TRANSMISSION - 46RE 21 - 149
AUTOMATIC TRANSMISSION - 46RE (Continued)

FLUID AND FILTER
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - EFFECTS OF
INCORRECT FLUID LEVEL
A low fluid level allows the pump to take in air
along with the fluid. Air in the fluid will cause fluid
pressures to be low and develop slower than normal.
If the transmission is overfilled, the gears churn the
fluid into foam. This aerates the fluid and causing
the same conditions occurring with a low level. In
either case, air bubbles cause fluid overheating, oxi-
dation and varnish buildup which interferes with
valve and clutch operation. Foaming also causes fluid
expansion which can result in fluid overflow from the
transmission vent or fill tube. Fluid overflow can eas-
ily be mistaken for a leak if inspection is not careful.
DIAGNOSIS AND TESTING - CAUSES OF
BURNT FLUID
Burnt, discolored fluid is a result of overheating
which has two primary causes.
(1) A result of restricted fluid flow through the
main and/or auxiliary cooler. This condition is usu-
ally the result of a faulty or improperly installed
drainback valve, a damaged main cooler, or severe
restrictions in the coolers and lines caused by debris
or kinked lines.
(2) Heavy duty operation with a vehicle not prop-
erly equipped for this type of operation. Trailer tow-
ing or similar high load operation will overheat the
transmission fluid if the vehicle is improperly
equipped. Such vehicles should have an auxiliary
transmission fluid cooler, a heavy duty cooling sys-
tem, and the engine/axle ratio combination needed to
handle heavy loads.
DIAGNOSIS AND TESTING - FLUID
CONTAMINATION
Transmission fluid contamination is generally a
result of:
²adding incorrect fluid
²failure to clean dipstick and fill tube when
checking level
²engine coolant entering the fluid
²internal failure that generates debris
²overheat that generates sludge (fluid break-
down)
²failure to replace contaminated converter after
repair
The use of non-recommended fluids can result in
transmission failure. The usual results are erratic
shifts, slippage, abnormal wear and eventual failuredue to fluid breakdown and sludge formation. Avoid
this condition by using recommended fluids only.
The dipstick cap and fill tube should be wiped
clean before checking fluid level. Dirt, grease and
other foreign material on the cap and tube could fall
into the tube if not removed beforehand. Take the
time to wipe the cap and tube clean before withdraw-
ing the dipstick.
Engine coolant in the transmission fluid is gener-
ally caused by a cooler malfunction. The only remedy
is to replace the radiator as the cooler in the radiator
is not a serviceable part. If coolant has circulated
through the transmission, an overhaul is necessary.
The torque converter should be replaced whenever
a failure generates sludge and debris. This is neces-
sary because normal converter flushing procedures
will not remove all contaminants.
STANDARD PROCEDURE
STANDARD PROCEDURE - FLUID LEVEL
CHECK
Low fluid level can cause a variety of conditions
because it allows the pump to take in air along with
the fluid. As in any hydraulic system, air bubbles
make the fluid spongy, therefore, pressures will be
low and build up slowly.
Improper filling can also raise the fluid level too
high. When the transmssion has too much fluid, the
geartrain churns up foam and cause the same condi-
tions which occur with a low fluid level.
In either case, air bubbles can cause overheating
and/or fluid oxidation, and varnishing. This can
interfere with normal valve, clutch, and accumulator
operation. Foaming can also result in fluid escaping
from the transmission vent where it may be mis-
taken for a leak.
After the fluid has been checked, seat the dipstick
fully to seal out water and dirt.
The transmission has a dipstick to check oil level.
It is located on the right side of the engine. Be sure
to wipe all dirt from dipstick handle before removing.
Fluid level is checked with the engine running at
curb idle speed, the transmission in NEUTRAL and
the transmission fluid at normal operating tempera-
ture.The engine should be running at idle
speed for at least one minute, with the vehicle
on level ground.
The transmission fluid level can be checked two
ways.
PROCEDURE ONE
(1) Transmission fluid must be at normal operat-
ing temperature for accurate fluid level check. Drive
DRAUTOMATIC TRANSMISSION - 46RE 21 - 201

CONDITION POSSIBLE CAUSES CORRECTION
BUZZING NOISE 1. Fluid Level Low 1. Add fluid and check for leaks.
2. Shift Cable Mis-assembled. 2. Route cable away from engine and bell
housing.
3. Valve Body Mis-assembled. 3. Remove, disassemble, inspect valve
body. Reassemble correctly if necessary.
Replace assembly if valves or springs are
damaged. Check for loose bolts or screws.
4. Pump Passages Leaking. 4. Check pump for porous casting, scores
on mating surfaces and excess rotor
clearance. Repair as required. Loose pump
bolts.
5. Cooling System Cooler Plugged. 5. Replace cooler.
6. Overrunning Clutch Damaged. 6. Replace clutch.
SLIPS IN REVERSE ONLY 1. Fluid Level Low. 1. Add fluid and check for leaks.
2. Gearshift Linkage Mis-adjusted. 2. Adjust linkage.
3. Rear Band Mis-adjusted. 3. Adjust band.
4. Rear Band Worn. 4. Replace as required.
5. Overdrive Direct Clutch Worn. 5. Disassemble overdrive. Repair as
needed.
6. Hydraulic Pressure Too Low. 6. Perform hydraulic pressure tests to
determine cause.
7. Rear Servo Leaking. 7. Air pressure check clutch-servo operation
and repair as required.
8. Band Linkage Binding. 8. Inspect and repair as required.
SLIPS IN FORWARD
DRIVE RANGES1. Fluid Level Low. 1. Add fluid and check for leaks.
2. Fluid Foaming. 2. Check for high oil level, bad pump
gasket or seals, dirt between pump halves
and loose pump bolts. Replace pump if
necessary.
3. Throttle Linkage Mis-adjusted. 3. Adjust linkage.
4. Gearshift Linkage Mis-adjusted. 4. Adjust linkage.
5. Rear Clutch Worn. 5. Inspect and replace as needed.
6. Low Hydraulic Pressure Due to
Worn Pump, Incorrect Control
Pressure Adjustments, Valve Body
Warpage or Malfunction, Sticking,
Leaking Seal Rings, Clutch Seals
Leaking, Servo Leaks, Clogged Filter
or Cooler Lines.6. Perform hydraulic and air pressure tests
to determine cause.
7. Rear Clutch Malfunction, Leaking
Seals or Worn Plates.7. Air pressure check clutch-servo operation
and repair as required.
8. Overrunning Clutch Worn, Not
Holding (Slips in 1 Only).8. Replace Clutch.
SLIPS IN LOW GEAR9D9
ONLY, BUT NOT IN
MANUAL 1 POSITIONOverrunning Clutch Faulty. Replace overrunning clutch.
21 - 330 AUTOMATIC TRANSMISSION - 48REDR
AUTOMATIC TRANSMISSION - 48RE (Continued)