2001 DODGE RAM engine

(14) Remove support and lower vehicle.
DIFFERENTIAL - TRAC-LOK
DIAGNOSIS AND TESTING - TRAC-LOKY
The most common problem is a chatter noise when
turning corners. Before removing a Trac-lokyunit
for repair, drain, flush and refill the axle with the
specified lubricant. A container of Mopar Trac-loky
Lubricant (friction modifier) should be added after
repair service or during a lubricant change.
After changing the lubricant, drive the vehicle and
make 10 to 12 slow, figure-eight turns. This maneu-
ver will pump lubricant through the clutches. This
will correct the condition in most instances. If the
chatter persists, clutch damage could have occurred.
DIFFERENTIAL TEST
The differential can be tested without removing the
differential case by measuring rotating torque. Make
sure brakes are not dragging during this measure-
ment.
(1) Place blocks in front and rear of both front
wheels.
(2) Raise one rear wheel until it is completely off
the ground.
(3) Engine off, transmission in neutral, and park-
ing brake off.(4) Remove wheel and bolt Special Tool 6790 or
equivalent tool to studs.
(5) Use torque wrench on special tool to rotate
wheel and read rotating torque (Fig. 35).
(6) If rotating torque is less than 22 N´m (30 ft.
lbs.) or more than 271 N´m (200 ft. lbs.) on either
wheel the unit should be serviced.
DISASSEMBLY
The Trac-Lokydifferential on this axle has a one-
piece cross shaft and uses one dished disc, regular 5
disc and 7 plates.
NOTE: Pay attention to the clutch pack arrangement
during disassembly. Note the direction of the con-
cave and convex side of the plates and discs.
(1) Mark the ring gear half and cover half for
installation reference (Fig. 36).
(2) Remove case attaching bolts and remove the
button cover half (Fig. 37).
(3) Remove top clutch pack.
(4) Remove top side gear clutch ring.
(5) Remove top side gear.
(6) Remove pinion mate gears and cross shaft.
(7) Remove the same parts listed above from the
ring gear flange half of the case. Keep these parts
with the flange cover half for installation in their
original positions.
ASSEMBLY
The Trac-Lokydifferential for this axle has a one-
piece cross shaft and uses one dished disc, 5 regular
disc and 7 plates for each clutch pack.
NOTE: The clutch discs are replaceable as com-
plete sets only. If one clutch disc pack is damaged,
both packs must be replaced.
Fig. 34 Differential Cover
1 - SEALANT SURFACE
2 - SEALANT
3 - SEALANT THICKNESS
Fig. 35 Trac-lokYTest - Typical
3 - 190 REAR AXLE - 286RBIBR/BE
DIFFERENTIAL (Continued)

RELEASE
REMOVAL..............................40
INSTALLATION...........................41SHOES
REMOVAL..............................41
INSTALLATION...........................42
BRAKES - BASE
SPECIFICATIONS
BASE BRAKE
SPECIFICATIONS
DESCRIPTION SPECIFICATION
Front/Rear Disc Brake
Caliper
TypeDual Piston Sliding
Front Disc Brake Caliper
Piston Diameter LD54 mm (2.00 in.)
Front Disc Brake Caliper
Piston Diameter HD56 mm (2.00 in.)
Front Disc Brake Rotor
1500 4x2304ý30 mm (11.96ý1.18
in.)
Front Disc Brake Rotor
1500 4x4307.5ý30 mm
(12.10ý1.18 in.)
Front Disc Brake Rotor
2500/3500326.5ý36 mm (12.5ý1.5
in.)
Front/Rear Disc Brake
Rotor
Max. Runout0.127 mm (0.005 in.)
Front/Rear Disc Brake
Rotor
Max. Thickness Variation0.025 mm (0.001 in.)
Mininium Front Rotor
Thickness
150028.39 mm (1.117 in.)
Minimum Front Rotor
Thickness
2500/350033.90 mm (1.334 in.)
Mininium Rear Rotor
Thickness
2500/350028.39 mm (1.117 in.)
DESCRIPTION SPECIFICATION
Drum Brake
Size
1500279ý57 mm (11ý2.25 in.)
Drum Brake
Size
2500/3500308ý89 mm (12.125ý3.5
in.)
Drum Brake
Max. Runout
15000.18 mm (0.007 in.)
Drum Brake
Max. Thickness Variation
15000.076 mm (0.003 in.)
Rear Disc Brake Caliper
25002x45 mm (1.77 in)
Rear Disc Brake Caliper
35002x51 mm (2.00 in)
Rear Disc Brake Rotor
2500/3500323.5x30 mm (1.18 in)
Wheel Cylinder Bore Size
150025.4 mm (1.00 in.)
Wheel Cylinder Bore Size
2500/350025.4 mm (1.00 in.)
Brake Booster
Type
1500/2500 Gasoline
EnginesVacuum Dual Diaphragm
Brake Booster
Type
All 3500/
2500 Diesel Engines
OnlyHydraulic
5 - 2 BRAKESBR/BE

DESCRIPTION N´m Ft. Lbs. In. Lbs.
Park Brake Pedal
Assembly
Mounting Bolts/Nuts28 21 250
Hub/Bearing
LD 4x2 Spindle Nut251 185 Ð
Hub/Bearing
HD 4x2 Spindle Nut380 280 Ð
Hub/Bearing
4x4 Hub/Bearing Bolts170 125 Ð
SPECIAL TOOLS
BASE BRAKES
HYDRAULIC/MECHANICAL
DESCRIPTION
This vehicle is equipped with front disc brakes and
rear drum brakes also certain vehicles have four
wheel disc brakes. The front and rear disc brakes
consist of dual piston calipers and ventilated rotors.
The rear brakes are dual brake shoe, internal
expanding units with cast brake drums. The parking
brake mechanism is cable operated and connected to
the rear brake trailing shoes. Power brake assist is
standard equipment. A vacuum operated power brake
booster is used on gas engine vehicles. A hydraulic
booster is used on diesel engine vehicles.
Two antilock brake systems are used on this vehi-
cle. A rear wheel antilock (RWAL) brake system and
all-wheel antilock brake system (ABS). The RWAL
and ABS systems are designed to retard wheel
lockup while braking. Retarding wheel lockup is
accomplished by modulating fluid pressure to the
wheel brake units. Both systems are monitored by a
microprocessor which controls the operation of the
systems.
Installer, Brake Caliper Dust Boot C-4340
Installer, Brake Caliper Dust Boot C-3716-A
Handle C-4171
Cap, Master Cylinder Pressure Bleed 6921
5 - 4 BRAKESBR/BE
BRAKES - BASE (Continued)

WARNING
WARNING: DUST AND DIRT ACCUMULATING ON
BRAKE PARTS DURING NORMAL USE MAY CON-
TAIN ASBESTOS FIBERS FROM PRODUCTION OR
AFTERMARKET LININGS. BREATHING EXCESSIVE
CONCENTRATIONS OF ASBESTOS FIBERS CAN
CAUSE SERIOUS BODILY HARM. EXERCISE CARE
WHEN SERVICING BRAKE PARTS. DO NOT CLEAN
BRAKE PARTS WITH COMPRESSED AIR OR BY
DRY BRUSHING. USE A VACUUM CLEANER SPE-
CIFICALLY DESIGNED FOR THE REMOVAL OF
ASBESTOS FIBERS FROM BRAKE COMPONENTS.
IF A SUITABLE VACUUM CLEANER IS NOT AVAIL-
ABLE, CLEANING SHOULD BE DONE WITH A
WATER DAMPENED CLOTH. DO NOT SAND, OR
GRIND BRAKE LINING UNLESS EQUIPMENT USED
IS DESIGNED TO CONTAIN THE DUST RESIDUE.
DISPOSE OF ALL RESIDUE CONTAINING ASBES-
TOS FIBERS IN SEALED BAGS OR CONTAINERS
TO MINIMIZE EXPOSURE TO YOURSELF AND OTH-
ERS. FOLLOW PRACTICES PRESCRIBED BY THE
OCCUPATIONAL SAFETY AND HEALTH ADMINIS-
TRATION AND THE ENVIRONMENTAL PROTECTION
AGENCY FOR THE HANDLING, PROCESSING, AND
DISPOSITION OF DUST OR DEBRIS THAT MAY
CONTAIN ASBESTOS FIBERS.
CAUTION: Never use gasoline, kerosene, alcohol,
motor oil, transmission fluid, or any fluid containing
mineral oil to clean the system components. These
fluids damage rubber cups and seals. Use only
fresh brake fluid or Mopar brake cleaner to clean or
flush brake system components. These are the only
cleaning materials recommended. If system contam-
ination is suspected, check the fluid for dirt, discol-
oration, or separation into distinct layers. Also
check the reservoir cap seal for distortion. Drain
and flush the system with new brake fluid if con-
tamination is suspected.
CAUTION: Use Mopar brake fluid, or an equivalent
quality fluid meeting SAE/DOT standards J1703 and
DOT 3. Brake fluid must be clean and free of con-
taminants. Use fresh fluid from sealed containers
only to ensure proper antilock component opera-
tion.
CAUTION: Use Mopar multi-mileage or high temper-
ature grease to lubricate caliper slide surfaces,
drum brake pivot pins, and shoe contact points on
the backing plates. Use multi-mileage grease or GE
661 or Dow 111 silicone grease on caliper slide pins
to ensure proper operation.
DIAGNOSIS AND TESTING - BASE BRAKE
SYSTEM
Base brake components consist of the brake shoes,
calipers, wheel cylinders, brake drums, rotors, brake
lines, master cylinder, booster, and parking brake
components.
Brake diagnosis involves determining if the prob-
lem is related to a mechanical, hydraulic, or vacuum
operated component.
The first diagnosis step is the preliminary check.
PRELIMINARY BRAKE CHECK
(1) Check condition of tires and wheels. Damaged
wheels and worn, damaged, or underinflated tires
can cause pull, shudder, vibration, and a condition
similar to grab.
(2) If complaint was based on noise when braking,
check suspension components. Jounce front and rear
of vehicle and listen for noise that might be caused
by loose, worn or damaged suspension or steering
components.
(3) Inspect brake fluid level and condition. Note
that the brake reservoir fluid level will decrease in
proportion to normal lining wear.Also note that
brake fluid tends to darken over time. This is
normal and should not be mistaken for contam-
ination.
(a) If fluid level is abnormally low, look for evi-
dence of leaks at calipers, wheel cylinders, brake
lines, and master cylinder.
(b) If fluid appears contaminated, drain out a
sample to examine. System will have to be flushed
if fluid is separated into layers, or contains a sub-
stance other than brake fluid. The system seals
and cups will also have to be replaced after flush-
ing. Use clean brake fluid to flush the system.
(4) Check parking brake operation. Verify free
movement and full release of cables and pedal. Also
note if vehicle was being operated with parking
brake partially applied.
(5) Check brake pedal operation. Verify that pedal
does not bind and has adequate free play. If pedal
lacks free play, check pedal and power booster for
being loose or for bind condition. Do not road test
until condition is corrected.
(6) Check booster vacuum check valve and hose.
(7) If components checked appear OK, road test
the vehicle.
ROAD TESTING
(1) If complaint involved low brake pedal, pump
pedal and note if it comes back up to normal height.
(2) Check brake pedal response with transmission
in Neutral and engine running. Pedal should remain
firm under constant foot pressure.
BR/BEBRAKES 5 - 5
HYDRAULIC/MECHANICAL (Continued)

front tire (bruised, ply separation) can also cause
pull.
A common and frequently misdiagnosed pull condi-
tion is where direction of pull changes after a few
stops. The cause is a combination of brake drag fol-
lowed by fade at one of the brake units.
As the dragging brake overheats, efficiency is so
reduced that fade occurs. Since the opposite brake
unit is still functioning normally, its braking effect is
magnified. This causes pull to switch direction in
favor of the normally functioning brake unit.
An additional point when diagnosing a change in
pull condition concerns brake cool down. Remember
that pull will return to the original direction, if the
dragging brake unit is allowed to cool down (and is
not seriously damaged).
REAR BRAKE GRAB OR PULL
Rear grab or pull is usually caused by improperly
adjusted or seized parking brake cables, contami-
nated lining, bent or binding shoes and support
plates, or improperly assembled components. This is
particularly true when only one rear wheel is
involved. However, when both rear wheels are
affected, the master cylinder or proportioning valve
could be at fault.
BRAKES DO NOT HOLD AFTER DRIVING THROUGH DEEP
WATER PUDDLES
This condition is generally caused by water soaked
lining. If the lining is only wet, it can be dried by
driving with the brakes very lightly applied for a
mile or two. However, if the lining is both soaked and
dirt contaminated, cleaning and/or replacement will
be necessary.
BRAKE LINING CONTAMINATION
Brake lining contamination is mostly a product of
leaking calipers or wheel cylinders, worn seals, driv-
ing through deep water puddles, or lining that has
become covered with grease and grit during repair.
Contaminated lining should be replaced to avoid fur-
ther brake problems.
WHEEL AND TIRE PROBLEMS
Some conditions attributed to brake components
may actually be caused by a wheel or tire problem.
A damaged wheel can cause shudder, vibration and
pull. A worn or damaged tire can also cause pull.
Severely worn tires with very little tread left can
produce a grab-like condition as the tire loses and
recovers traction. Flat-spotted tires can cause vibra-
tion and generate shudder during brake operation. A
tire with internal damage such as a severe bruise,
cut, or ply separation can cause pull and vibration.BRAKE NOISES
Some brake noise is common with rear drum
brakes and on some disc brakes during the first few
stops after a vehicle has been parked overnight or
stored. This is primarily due to the formation of trace
corrosion (light rust) on metal surfaces. This light
corrosion is typically cleared from the metal surfaces
after a few brake applications causing the noise to
subside.
BRAKE SQUEAK/SQUEAL
Brake squeak or squeal may be due to linings that
are wet or contaminated with brake fluid, grease, or
oil. Glazed linings and rotors with hard spots can
also contribute to squeak. Dirt and foreign material
embedded in the brake lining will also cause squeak/
squeal.
A very loud squeak or squeal is frequently a sign of
severely worn brake lining. If the lining has worn
through to the brake shoes in spots, metal-to-metal
contact occurs. If the condition is allowed to continue,
rotors and drums can become so scored that replace-
ment is necessary.
BRAKE CHATTER
Brake chatter is usually caused by loose or worn
components, or glazed/burnt lining. Rotors with hard
spots can also contribute to chatter. Additional causes
of chatter are out-of-tolerance rotors, brake lining not
securely attached to the shoes, loose wheel bearings
and contaminated brake lining.
THUMP/CLUNK NOISE
Thumping or clunk noises during braking are fre-
quentlynotcaused by brake components. In many
cases, such noises are caused by loose or damaged
steering, suspension, or engine components. However,
calipers that bind on the slide surfaces can generate
a thump or clunk noise. In addition, worn out,
improperly adjusted, or improperly assembled rear
brake shoes can also produce a thump noise.
STANDARD PROCEDURE - MANUAL BLEEDING
Use Mopar brake fluid, or an equivalent quality
fluid meeting SAE J1703-F and DOT 3 standards
only. Use fresh, clean fluid from a sealed container at
all times.
(1) Remove reservoir filler caps and fill reservoir.
(2) If calipers, or wheel cylinders were overhauled,
open all caliper and wheel cylinder bleed screws.
Then close each bleed screw as fluid starts to drip
from it. Top off master cylinder reservoir once more
before proceeding.
(3) Attach one end of bleed hose to bleed screw
and insert opposite end in glass container partially
BR/BEBRAKES 5 - 7
HYDRAULIC/MECHANICAL (Continued)

SPECIFICATIONS
BRAKE FLUID
The brake fluid used in this vehicle must conform
to DOT 3 specifications and SAE J1703 standards.
No other type of brake fluid is recommended or
approved for usage in the vehicle brake system. Use
only Mopar brake fluid or an equivalent from a
tightly sealed container.
CAUTION: Never use reclaimed brake fluid or fluid
from an container which has been left open. An
open container of brake fluid will absorb moisture
from the air and contaminate the fluid.
CAUTION: Never use any type of a petroleum-based
fluid in the brake hydraulic system. Use of such
type fluids will result in seal damage of the vehicle
brake hydraulic system causing a failure of the
vehicle brake system. Petroleum based fluids would
be items such as engine oil, transmission fluid,
power steering fluid, etc.
FLUID RESERVOIR
REMOVAL
(1) Remove reservoir cap and empty fluid into
drain container.
(2) Clamp cylinder body in vise with brass protec-
tive jaws.
(3) Remove pins that retain reservoir to master
cylinder. Use hammer and pin punch to remove pins
(Fig. 18).
(4) Loosen reservoir from grommets with pry tool
(Fig. 19).
(5) Remove reservoir by rocking it to one side and
pulling free of grommets (Fig. 20).
(6) Remove old grommets from cylinder body (Fig.
21).
INSTALLATION
CAUTION: Do not use any type of tool to install the
grommets. Tools may cut, or tear the grommets cre-
ating a leak problem after installation. Install the
grommets using finger pressure only.
(1) Lubricate new grommets with clean brake fluid
and Install new grommets in cylinder body (Fig. 22).
Use finger pressure to install and seat grommets.(2) Start reservoir in grommets. Then rock reser-
voir back and forth while pressing downward to seat
it in grommets.
(3) Install pins that retain reservoir to cylinder
body.
(4) Fill and bleed master cylinder on bench before
installation in vehicle.
Fig. 18 Reservoir Retaining Pins
1 - PIN PUNCH
2 - RESERVOIR
3 - BODY
4 - ROLL PINS
Fig. 19 Loosening Reservoir
1-PRYTOOL
2 - RESERVOIR
3 - GROMMET
4 - MASTER CYLINDER BODY
BR/BEBRAKES 5 - 15
FLUID (Continued)

(8) Push pedal shaft back and out of passenger
side of bracket (Fig. 24).
(9) Remove pedal shaft, brake pedal, wave washer
and bushings from vehicle.
INSTALLATION
(1) Replace bracket and pedal bushings if neces-
sary. Lubricate shaft bores in bracket and pedal
before installing bushings with Mopar Multi-mileage
silicone grease.
(2) Apply liberal quantity of Mopar multi-mileage
grease to pedal shaft and to pedal and bracket bush-
ings.
(3) Position brake pedal in mounting bracket.
(4) Slide pedal shaft into bracket and through
pedal from passenger side.
(5) Push pedal shaft out driver side of mounting
bracket just enough to allow installation of retaining
E-clip.
(6) Install the wave washer between the bracket
and the pedal bushing on the passenger side.
(7) Push pedal shaft back toward passenger side of
bracket and install remaining E-clip on pedal shaft.
(8) Install booster push rod on brake pedal. Secure
push rod to pedal with washer and retaining clip.
(9) Install brake lamp switch bracket and switch,
(Refer to 8 - ELECTRICAL/LAMPS/LIGHTING -EXTERIOR/BRAKE LAMP SWITCH - INSTALLA-
TION).
(10) Install knee bolster, (Refer to 23 - BODY/IN-
STRUMENT PANEL/STEERING COLUMN OPEN-
ING COVER - INSTALLATION).
POWER BRAKE BOOSTER
DIAGNOSIS AND TESTING - HYDRAULIC
BOOSTER
The hydraulic booster uses hydraulic pressure from
the power steering pump. Before diagnosing a
booster problem, first verify the power steering pump
is operating properly. Perform the following checks.
²Check the power steering fluid level.
²Check the brake fluid level.
²Check all power steering hoses and lines for
leaks and restrictions.
²Check power steering pump pressure.
NOISES
The hydraulic booster unit will produce certain
characteristic booster noises. The noises may occur
when the brake pedal is used in a manner not asso-
ciated with normal braking or driving habits.
HISSING
A hissing noise may be noticed when above normal
brake pedal pressure is applied, 40 lbs. or above. The
noise will be more noticeable if the vehicle is not
moving. The noise will increase with the brake pedal
pressure and an increase of system operating temper-
ature.
CLUNK-CHATTER-CLICKING
A clunk-chatter-clicking may be noticed when the
brake pedal is released quickly, after above normal
brake pedal pressure is applied 50-100 lbs..
BOOSTER FUNCTION TEST
With the engine off depress the brake pedal several
times to discharge the accumulator. Then depress the
brake pedal using 40 lbs. of force and start the
engine. The brake pedal should fall and then push
back against your foot. This indicates the booster is
operating properly.
ACCUMULATOR LEAKDOWN
(1) Start the engine, apply the brakes and turn the
steering wheel from lock to lock. This will ensure the
accumulator is charged. Turn off the engine and let
the vehicle sit for one hour. After one hour there
should be at least two power assisted brake applica-
tion with the engine off. If the system does not retain
a charge the booster must be replaced.
Fig. 24 Brake Pedal Mounting (With Automatic
Transmission)
1 - PEDAL SHAFT
2 - SHAFT RETAINING E-CLIPS (2)
3 - BRAKE PEDAL
4 - PEDAL BUSHING (2)
5 - PEDAL MOUNTING BRACKET
BR/BEBRAKES 5 - 17
PEDAL (Continued)

(2) With the engine off depress the brake pedal
several times to discharge the accumulator. Grasp
the accumulator and see if it wobbles or turns. If it
does the accumulator has lost a gas charge and the
booster must be replaced.
SEAL LEAKAGE
If the booster leaks from any of the seals the
booster assembly must be replaced (Fig. 25).
²INPUT ROD SEAL:Fluid leakage from rear
end of the booster.
²PISTON SEAL:Fluid leakage from vent at
front of booster.
²HOUSING SEAL:Fluid leakage between hous-
ing and housing cover.
²SPOOL VALVE SEAL:Fluid leakage near
spool plug.
²RETURN PORT FITTING SEAL:Fluid leak-
age from port fitting.
HYDRAULIC BOOSTER DIAGNOSIS CHART
CONDITION POSSIBLE CAUSES CORRECTION
Slow Brake Pedal Return 1. Excessive seal friction in booster. 1. Replace booster.
2. Faulty spool valve action. 2. Replace booster.
3. Restriction in booster return hose. 3. Replace hose.
4. Damaged input rod. 4. Replace booster.
Excessive Brake Pedal
Effort.1. Internal or external seal leakage. 1. Replace booster.
2. Faulty steering pump. 2. Replace pump.
Brakes Self Apply 1. Dump valve faulty. 1. Replace booster.
2. Contamination in hydraulic
system.2. Flush hydraulic system and replace
booster.
3. Restriction in booster return hose. 3. Replace hose.
Booster Chatter, Pedal
Vibration1. Slipping pump belt. 1. Replace power steering belt.
2. Low pump fluid level. 2. Fill pump and check for leaks.
Grabbing Brakes 1. Low pump flow. 1. Test and repair/replace pump.
2. Faulty spool valve action. 2. Replace booster.
Fig. 25 Hydraulic Booster Seals
1 - PUMP
2 - GEAR
3 - INPUT SEAL
4 - HOUSING SEAL
5 - ACCUMULATOR SEAL
6 - PISTON SEAL
7 - SPOOL PLUG SEAL
8 - RETURN
5 - 18 BRAKESBR/BE
POWER BRAKE BOOSTER (Continued)