differential DODGE RAM 2001 Service Repair Manual

GEAR CONTACT PATTERN ANALYSIS
The ring gear and pinion teeth contact patterns
will show if the pinion depth is correct in the axle
housing. It will also show if the ring gear backlash
has been adjusted correctly. The backlash can be
adjusted within specifications to achieve desired
tooth contact patterns.
(1) Apply a thin coat of hydrated ferric oxide, or
equivalent, to the drive and coast side of the ring
gear teeth.
(2) Wrap, twist, and hold a shop towel around the
pinion yoke to increase the turning resistance of the
pinion. This will provide a more distinct contact pat-
tern.
(3) Using a boxed end wrench on a ring gear bolt,
Rotate the differential case one complete revolution
in both directions while a load is being applied from
shop towel.
The areas on the ring gear teeth with the greatest
degree of contact against the pinion teeth will squee-
gee the compound to the areas with the least amount
of contact. Note and compare patterns on the ring
gear teeth to Gear Tooth Contact Patterns chart (Fig.
21)and adjust pinion depth and gear backlash as nec-
essary.
Fig. 20 Backlash Shim Adjustment
3 - 180 REAR AXLE - 286RBIBR/BE
REAR AXLE - 286RBI (Continued)

SPECIFICATIONS
REAR AXLE - 286RBI
AXLE SPECIFICATIONS
DESCRIPTION SPECIFICATION
Axle Ratio 3.55, 4.10
Ring Gear Diameter 286 mm (11.25 in.)
Ring Gear Backlash 0.12-0.20 mm (0.005-0.008 in.)
Pinion Gear Standard Depth 147.625 mm (5.812 in.)
Pinion Bearing Preload - Original Bearings 1-2 N´m (10-20 in. lbs.)
Pinion Bearing Preload - New Bearings 2.8-5.1 N´m (25-45 in. lbs.)
TORQUE SPECIFICATIONS
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Fill Hole Plug 34 25 -
Differential Cover Bolts 47 35 -
Bearing Cap Bolts 108 80 -
Ring Gear Bolt 298 220 -
Pinion Nut 597-678 440-500 -
Axle Shaft Bolts 128 95 -
Hub Bearing Nut 163-190 120-140 -
Trac-LocYCase Bolts 122-136 90-100 -
SPECIAL TOOLS
REAR AXLE - 286 RBI
Puller, Hub 6790
Wrench DD-1241-JD
Installer 5064
Installer C-4308
3 - 182 REAR AXLE - 286RBIBR/BE
REAR AXLE - 286RBI (Continued)

NOTE: The seal is correctly installed when the seal
flange contacts the face of the differential housing
flange.
(6) Position pinion yoke on the end of the shaft
with the reference marks aligned.
(7) Seat yoke on pinion shaft with Installer D-191
and Yoke Holder 6719 (Fig. 23).
(8) Remove the tools and install the pinion yoke
washer and nut.
(9) Hold pinion yoke with Yoke Holder 6719 and
tighten shaft nut to 597 N´m (440 ft. lbs.) (Fig. 24).
Rotate pinion shaft several revolutions to ensure the
bearing rollers are seated.
(10) Rotate the pinion shaft using an inch pound
torque wrench. Rotating resistance torque should be
equal to the reading recorded, plus a small amount
for the drag the new seal will have (Fig. 25).
NOTE: The bearing rotating torque should be con-
stant during a complete revolution of the pinion. If
the rotating torque varies, this indicates a binding
condition.
(11) Install the propeller shaft with the installa-
tion reference marks aligned.
(12) Tighten the universal joint yoke clamp screws
to 19 N´m (14 ft. lbs.).
(13) Install the brake drums.
(14) Add gear lubricant to the differential housing,
if necessary. Refer to the Lubricant Specifications for
gear lubricant requirements.
(15) Install wheel and tire assemblies and lower
the vehicle.
Fig. 22 Yoke Removal
1 - PINION YOKE
2 - REMOVER C452
Fig. 23 Yoke Installation
1 - YOKE INSTALLER
2 - YOKE HOLDER
Fig. 24 Tightening Pinion Shaft Nut
1 - DIFFERENTIAL HOUSING
2 - YOKE HOLDER
3 - TORQUE WRENCH
3 - 186 REAR AXLE - 286RBIBR/BE
PINION SEAL (Continued)

DIFFERENTIAL
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the lubricant fill hole plug from the
differential housing cover.
(3) Remove differential housing cover and drain
the lubricant from the housing.
(4) Clean the housing cavity with a flushing oil,
light engine oil or lint free cloth.Do not use water,
steam, kerosene or gasoline for cleaning.
(5) Remove axle shafts.
(6) Note the orientation of the installation refer-
ence letters stamped on the bearing caps and hous-
ing machined sealing surface (Fig. 26).
(7) Remove the differential bearing caps.
(8) Position Spreader W-129-B with the tool dowel
pins seated in the locating holes (Fig. 27).
(9) Install the hold down clamps and tighten the
tool turnbuckle finger-tight.
(10) Install a Pilot Stud C-3288-B at the left side
of the differential housing. Attach dial indicator to
housing pilot stud. Load the indicator plunger
against the opposite side of the housing (Fig. 27) and
zero the indicator.
(11) Spread the housing enough to remove the case
from the housing. Measure the distance with the dial
indicator (Fig. 27).CAUTION: Do not spread over 0.50 mm (0.020 in). If
the housing is over-spread, it could be distorted or
damaged.
(12) Remove the dial indicator.
(13) Pry the differential case loose from the hous-
ing. To prevent damage, pivot on housing with the
end of the pry bar against spreader (Fig. 28).
(14) Remove the case from housing. Tag bearing
cups to indicate their location.
Fig. 25 Check Pinion Rotation Torque
1 - PINION YOKE
2 - INCH POUND TORQUE WRENCH
Fig. 26 Bearing Cap Identification
1 - REFERENCE LETTERS
2 - REFERENCE LETTERS
Fig. 27 Spread Differential Housing
1 - SPREADER
2 - DIAL INDICATOR
3 - DIFFERENTIAL
4 - DIFFERENTIAL HOUSING
5 - PILOT STUD
BR/BEREAR AXLE - 286RBI 3 - 187
PINION SEAL (Continued)

DISASSEMBLY
(1) Remove roll-pin holding mate shaft in housing.
(2) Remove pinion gear mate shaft (Fig. 29).
(3) Rotate the differential side gears and remove
the pinion mate gears and thrust washers (Fig. 30).(4) Remove the differential side gears and thrust
washers.
ASSEMBLY
(1) Install the differential side gears and thrust
washers.
(2) Install the pinion mate gears and thrust wash-
ers.
(3) Install the pinion gear mate shaft.
(4) Align the hole in the pinion gear mate shaft
with the hole in the differential case.
(5) Install and seat the pinion mate shaft roll-pin
in the differential case and mate shaft with a punch
and hammer (Fig. 31). Peen the edge of the roll-pin
hole in the differential case slightly in two places,
180É apart.
(6) Lubricate all differential components with
hypoid gear lubricant.
INSTALLATION
NOTE: If replacement differential bearings or differ-
ential case are being installed, differential side
bearing shim requirements may change. Refer to
Adjustments (Differential Bearing Preload and Gear
Backlash) procedures to determine proper shim
selection.
Fig. 28 Differential Removal
1 - DIFFERENTIAL
2-PRYBAR
Fig. 29 Pinion Mate Shaft
1 - PINION MATE GEAR
2 - PINION MATE SHAFT
3 - SIDE GEAR
4 - DRIFT
Fig. 30 Pinion Mate/Side Gear
1 - THRUST WASHER
2 - SIDE GEAR
3 - PINION MATE GEAR
3 - 188 REAR AXLE - 286RBIBR/BE
DIFFERENTIAL (Continued)

(1) Position Spreader W-129-B with the tool dowel
pins seated in the locating holes. Install the hold
down clamps and tighten the tool turnbuckle finger-
tight.
(2) Install a Pilot Stud C-3288-B at the left side of
the differential housing and attach dial indicator to
the pilot stud. Load the indicator plunger against the
opposite side of the housing and zero the dial indica-
tor.
(3) Spread the housing enough to install the case
in the housing. Measure the distance with the dial
indicator.
CAUTION: Do not spread over 0.50 mm (0.020 in). If
the housing is over-spread, it could be distorted or
damaged.
(4) Remove the dial indicator.
(5) Install differential into the housing. Tap the
differential case with a rawhide/rubber hammer to
ensure the bearings are seated in housing (Fig. 32).
(6) Remove the spreader.
(7) Install bearing caps in their original locations
(Fig. 33) and tighten bearing cap bolts to 109 N´m
(80 ft. lbs.).
(8) Install axle shafts.
(9) Install the hub bearings.
(10) Apply a bead of Mopar Silicone Rubber Seal-
ant or equivalent to the housing cover (Fig. 34).Install the housing cover within 5 minutes
after applying the sealant.
(11) Install the cover and any identification tag.
Tighten the cover bolts in a criss-cross pattern to 47
N´m (35 ft. lbs.).
(12) Refill the differential with Mopar Hypoid
Gear Lubricant or equivalent to bottom of the fill
plug hole. Refer to the Lubricant Specifications for
correct quantity and type.
(13) Install the fill hole plug and tighten to 34 N´m
(25 ft. lbs.).
Fig. 31 Pinion Mate Shaft Roll-Pin
1 - PUNCH
2 - PINION MATE SHAFT
3 - MATE SHAFT LOCKPIN
Fig. 32 Differential Case
1 - RAWHIDE HAMMER
Fig. 33 Bearing Cap Reference
1 - REFERENCE LETTERS
2 - REFERENCE LETTERS
BR/BEREAR AXLE - 286RBI 3 - 189
DIFFERENTIAL (Continued)

(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)

Lubricate each component with gear lube before
assembly and installation.(1) Saturate the clutch plates with Mopar Hypoid
Gear Lubricant or Additive.
(2) Assembly the discs and plates on the side gear
(Fig. 38) in the following order.
(a) Install dished disc on side gear.
(b) Install one disc on side gear.
(c) Install one plate on side gear.
(d) Install one disc on side gear.
(e) Install one plate on side gear.
(f) Install three discs on side gear.
(g) Install five plates on side gear.
(3) Line up the plate ears and install the assem-
bled pack into the flange half (Fig. 39). Verify clutch
plate lugs enter the slots in the case and clutch pack
bottoms out in the case.
(4) Install pinion mate shafts and pinion mate
gears (Fig. 40).Verify shafts are correctly
installed according to the alignment marks.
(5) Lubricate and install the other side gear and
clutch pack (Fig. 39).
(6) Correctly align and assemble button half to
flange half. Install case body screws finger tight.
(7) Tighten body screws alternately and evenly.
Tighten screws to 122-136 N´m (90-100 ft. lbs.) (Fig.
41).
Fig. 36 Case Marked
1 - REFERENCE MARKS
Fig. 37 Cover Half Removal
1 - CLUTCH PLATES
2 - BUTTON HALF
3 - FLANGE HALF
Fig. 38 Clutch Pack Assembly
1 - CLUTCH PLATES
2 - SIDE GEAR
3 - CLUTCH RING
BR/BEREAR AXLE - 286RBI 3 - 191
DIFFERENTIAL - TRAC-LOK (Continued)

DIFFERENTIAL CASE
BEARINGS
REMOVAL
(1) Remove differential case from axle housing.
(2) Remove the bearings from the differential case
with Press 938 and Bearing Splitter 1130 (Fig. 42).
INSTALLATION
If ring and pinion gears have been replaced, verify
differential side bearing preload and gear mesh back-
lash.
(1) Using tool C-4190 with handle C-4171, install
differential side bearings (Fig. 43).
(2) Install differential in axle housing.
Fig. 39 Clutch Pack
1 - LUGS
2 - FLANGE HALF
3 - SIDE GEAR
Fig. 40 Clutch Pack
1 - CLUTCH PACK
2 - SIDE GEAR
3 - PINION GEARS AND MATE SHAFT
4 - ALIGNMENT MARKS
Fig. 41 Case Halfs
1 - FIXTURE
2 - CASE BOLTS
3 - TORQUE WRENCH
3 - 192 REAR AXLE - 286RBIBR/BE
DIFFERENTIAL - TRAC-LOK (Continued)

PINION GEAR/RING GEAR/
TONE RING
REMOVAL
NOTE: The ring and pinion gears are service in a
matched set. Do not replace the ring gear without
replacing the matched pinion gear.
(1) Remove differential from axle housing.
(2) Place differential case in a vise with soft metal
jaw protectors. (Fig. 44)
(3) Remove bolts holding ring gear to differential
case.
(4) Drive ring gear from differential case with a
soft hammer (Fig. 44).
(5) Use a brass drift and slowly tap the exciter
ring from the differential case.
(6) Mark pinion yoke and propeller shaft for
installation alignment.
(7) Disconnect propeller shaft from pinion yoke.
Tie propeller shaft to underbody.
(8) Using Yoke Holder 6719 to hold yoke, remove
pinion yoke nut and washer.
(9) Remove pinion yoke from pinion with Remover
C-452 and Wrench C-3281, shaft (Fig. 45).
(10) Remove pinion gear from housing (Fig. 46).
(11) Remove pinion seal with a slide hammer or
pry bar.
(12) Remove oil slinger, if equipped, and the front
pinion bearing.
Fig. 42 Differential Bearing Removal
1 - BRIDGE 938
2 - TOOL 1130
3 - DIFFERENTIAL
Fig. 43 Install Differential Side Bearings
1 - HANDLE C-4171
2 - DIFFERENTIAL CASE
3 - BEARING
4 - TOOL C-4190
Fig. 44 Ring Gear Removal
1 - DIFFERENTIAL CASE
2 - RING GEAR
3 - HAMMER
BR/BEREAR AXLE - 286RBI 3 - 193
DIFFERENTIAL CASE BEARINGS (Continued)