1999 DODGE RAM engine


DRIV E A XLE - F B I S EM I- F LO ATIN G
1999 D odge P ic ku p R 1500
1998-99 DRIVE AXLES
CHRY - FBI Semi-Floating Axles
Ram Pickup
IDENTIFICATION
DRIVE AXLE APPLICATION








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Application Axle Ring Axle
Model Gear Size Ratio
Front Axle ........ 216 FBI ......... 8.50" .. 3.54, 3.92 & 4.09
Front Axle ........ 248 FBI ......... 9.75" ........ 3.54 & 4.10









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DESCRIPTION & OPERATION
The Front Beam-Design Iron (FBI) axles is of an iron center
casting (differential housing) with axle shaft tubes extending from
both sides. The tubes are pressed in to form a one-piece axle housing
and is a semi-floating design.
Axle contains an integral carrier with hypoid-type ring gear
and pinion with semi-floating axle shafts. Load is supported by hub
bearings. Axle shafts are retained by nuts at the hub bearings. Hub
bearings are bolted to steering knuckle at outboard end of axle tube
yoke. Hub bearings are serviced as an assembly. On vehicles equipped
with Anti-Lock (ABS) brakes, a brake sensor is mounted on knuckle
assemblies, and tone rings are pressed onto axle shaft.
Differential is a one-piece design and differential pinion
mate shaft is retained with a roll pin. Differential bearing preload
and ring gear backlash is adjusted by use of shims, and pinion bearing
preload is set and maintained by use of a collapsible spacer.
Axle shaft is engaged or disengaged by an axle vacuum shift
motor. Vacuum shift motor is operated by engine vacuum and is
controlled by a switch mounted on transfer case.
AXLE RATIO & IDENTIFICATION
NOTE: Axle ratio can be identified by axle identification tag
attached to axle housing cover. See IDENTIFICATION.
LUBRICATION
CAPACITY
DRIVE AXLE CAPACITY ( 1)








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Application Pts. (L)\
216 FBI .................................................. 4.8 (2.3)\
248 FBI .................................................. 7.6 (3.6)\
(1) - Approximate drive axle capacity listed. Lubricant level should
be 1/2" below oil filler hole in axle housing cover.









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DRIV E A XLE S - P O W ER -L O K

1999 D odge P ic ku p R 1500
1998-99 DRIVE AXLES
CHRY - Power-Lok
Ram Pickup
IDENTIFICATION
POWER-LOK DIFFERENTIAL APPLICATION








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Application Axle Ring Axle
Model Gear Size Ratio
Ram Pickup ........ Rear Axle ... 10.5" (266.7 mm) ..... 267 RBI\









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NOTE: For rear axles with limited-slip differentials, see TRAC-LOK
article.
DESCRIPTION & OPERATION
A Rear Beam-Design Iron (RBI) axle is an iron casting axle
and differential housing with axle shaft tubes extending from either
side. Tubes are pressed to form a one-piece full-floating axle
housing.
Power-Lok differential assembly is optional equipment. The
differential assembly is a limited-slip type differential. It is
similar in operation to a conventional type differential, except for 2
clutch packs located at the side gears in the differential case. See
Fig. 1 . Clutch packs provide differential action when required for
turning corners, and transmit equal torque to both wheels when driving
straight ahead.
AXLE RATIO & IDENTIFICATION
Axle ratio can be identified by axle identification tag
attached to axle housing cover. See AXLE RATIO SPECIFICATIONS table.
AXLE RATIO SPECIFICATIONS









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Application Ratio
Ram Pickup ......................................... 3.54:1 & 4.10:1









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WARNING: Whenever rotating wheels, DO NOT use engine to rotate
individual wheels unless both rear wheels are off ground and
vehicle is securely supported.
LUBRICATION
CAPACITY
DRIVE AXLE CAPACITY ( 1)








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Application Pts. (L)\
Ram Pickup ........................................... ( 2) 7.0 (3.3)

(1) - Approximate drive axle capacity listed. Lubricant level should
be within 1/2" below bottom of oil filler hole in axle housing
cover.
( 2) - Add container of Mopar Gear Oil Friction Modifier when
refilling.









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FLUID TYPE
Use SAE 80W-90 or SAE 90W hypoid gear lubricant with MIL-L-
2105-B and API GL-5 ratings. Also add a container of Mopar Gear Oil
Friction Modifier when refilling.
FLUID DRAIN & REFILL
1) With lubricant of rear axle assembly at normal operating
temperature, raise and support vehicle so rear wheels are free to
rotate. Clean around axle housing cover. Loosen axle housing cover
bolts. Drain lubricant from axle housing. Remove bolts and axle
housing cover.
2) Position differential so hole in differential case faces
down. Wipe all accessible areas of axle housing. Ensure sealing
surfaces on axle housing and cover are clean. Apply a 1/4" thick bead
of silicone sealant on inside of bolt holes and along sealing surfaces
on axle housing cover.
3) Install axle housing cover, axle identification tag and
retaining bolts. Tighten bolts to 30 ft. lbs. (41 N.m). Remove oil
filler plug. Add a container of Mopar Gear Oil Friction Modifier. Fill
axle with gear lube. Install oil filler plug. Lower vehicle.
TROUBLE SHOOTING
DIFFERENTIAL NOISE
1) Ensure differential lubricant is at normal operating
temperature. Road test vehicle. Note if differential noise exists in
turns, but not during straight-ahead driving. Probable cause is
incorrect or insufficient rear axle lubricant or additive.
2) Drain and refill rear axle. See FLUID DRAIN & REFILL under
LUBRICATION. Road test vehicle and note if noise still exists, it may
be necessary to disassemble rear axle so differential can be repaired.
See RBI FULL-FLOATING AXLES article for removal of differential case.
TESTING
NOTE: Power-Lok differential can be tested without removing
differential carrier from axle housing. Either test can be
used to check drive axle.
TEST I
1) Place blocks under both front wheels. Ensure engine is off
and transmission is in Neutral. Release parking brake. Raise one rear
wheel until it is completely clear of the floor. Remove wheel. Install
Adapter (6790) to wheel studs, and tighten securely.
2) Using torque wrench on adapter, rotate axle, and record
torque required. Repeat procedure for remaining rear wheel position.
If rotational torque for either rear wheel is less than 30 ft. lbs.
(41 N.m) or greater than 200 ft. lbs. (271 N.m), Power-Lok unit must\
be replaced or repaired.


DRIV E A XLE - T R AC -L O K

1999 D odge P ic ku p R 1500
1998-99 DRIVE AXLES
CHRY - Trac-Lok
Dakota, Ram Pickup, Ram Van/Wagon
IDENTIFICATION
TRAC-LOK DIFFERENTIAL APPLICATION (REAR AXLE)








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Model Ring Gear Axle
Size Model
Dakota .................... 8 1/4" ........................... ( 1)
Ram Pickup ............ 9 3/4" ....................... 248 RBI
10 3/4" ....................... 267 RBI
11" ....................... 286 RBI
Ram Van/Wagon ............. 9 3/4" ....................... 248 RBI
( 1) - Manufacturer does not designate axle model.









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NOTE: For rear axles with limited-slip differentials, see POWER-LOK
- RAM PICKUP article.
DESCRIPTION & OPERATION
A Rear Beam-Design Iron (RBI) axle is an iron casting axle
and differential housing with axle shaft tubes extending from either
side. Tubes are pressed in to form a one-piece full-floating axle
housing.
Trac-Lok differential assembly is optional equipment. The
Trac-Lok differential assembly is a limited-slip type differential. It
is similar in operation to a conventional type differential, except
for 2 clutch packs located at the side gears in the differential case.
See Fig. 1 . Clutch packs provide differential action when required for
turning corners, and transmit equal torque to both wheels when driving
straight ahead.
AXLE RATIO & IDENTIFICATION
Axle ratio can be identified by axle identification tag
attached to axle housing cover. See AXLE RATIO SPECIFICATIONS table.
AXLE RATIO SPECIFICATIONS









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Application Ratio
Dakota ..................................... 3.21:1, 3.55:1 & 3.92:1
Ram Pickup
248 RBI .......................................... 3.55:1 & 4.10:1
267 & 286 RBI .................................... 3.54:1 & 4.10:1
Ram Van/Wagon ...................................... 3.55:1 & 4.10:1









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WARNING: Whenever rotating wheels, DO NOT use engine to rotate wheels
unless both rear wheels are off the ground and vehicle is
securely supported.

TESTING
NOTE: Trac-Lok differential can be tested without removing
differential case from axle housing.
1) Place blocks under both front wheels. Ensure engine is off
and transmission is in Neutral. Release parking brake. Raise one rear
wheel until it is completely clear of the floor. Remove wheel. Install
Adapter (6790) to wheel studs and tighten securely.
2) Using torque wrench on adapter, rotate axle and record
torque required. Repeat procedure for remaining rear wheel position.
If rotational torque for either rear wheel is less than 30 ft. lbs.
(40.1 N.m) or greater than 200 ft. lbs. (271 N.m), Trac-Lok unit mus\
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be replaced or repaired.
REMOVAL & INSTALLATION
Servicing procedure is same as that used for standard
differential. See RBI FULL FLOATING AXLES article for servicing
procedures.
OVERHAUL
DIFFERENTIAL CARRIER
Disassembly
1) Place appropriate side gear holding tool in soft-jaw vise.
Position differential carrier on holding tool. Remove ring gear, if
necessary. Ring gear removal is only necessary when ring gear is being
replaced.
2) Remove roll pin holding pinion mate shaft into housing.
Remove pinion gear mate shaft. A drift and hammer can be used if
necessary. See Fig. 1.
3) Install appropriate Step Plate on lower side gear. Install
appropriate threaded forcing screw into upper side gear. See Fig. 2.
4) Thread Forcing Screw into threaded adapter disc until
forcing screw is centered in threaded adapter disc. Perform STEP 1
shown in illustration. See Fig. 2.
5) Place small screwdriver in slot of threaded adapter disc
to prevent disc from rotating. Tighten forcing screw to relieve
tension from clutch pack.
6) Remove pinion gear thrust washers. Loosen forcing screw to
release pressure from clutch pack. Install appropriate turning bar in
hole on side of differential case. Perform STEP 2 shown in
illustration. See Fig. 2.
7) Using turning bar, rotate differential case until pinion
gears can be removed. Remove pinion gears. Remove turning bar, forcing
screw, step plate, and threaded adapter disc from differential case.
8) Remove upper side gear and clutch pack. See Fig. 1. Remove
differential case from axle shaft. Remove remaining side gear and
clutch pack from differential case.
CAUTION: Mark clutch pack location for reassembly reference. Note
position of clutch pack components before removing clutch
pack retainers. Clutch packs must be assembled in correct
order and installed in original location.
9) Remove clutch pack retainers from clutch pack. Keeping
clutch pack components in correct order, disassemble clutch pack.

Apply multipurpose lubricant (NLGI grade 2 EP) to "U" joints
and slip joint fittings.
INSPECTION
Abnormal vibration and noise can come from many driveline
sources. Drive shaft vibration/noise increases with vehicle speed
(MPH). A vibration that occurs within a specific speed is not caused
by drive shaft imbalance. Before overhauling driveline, check for
other causes/sources of possible vibration/noise.
TIRES & WHEELS
Check tire inflation and wheel balance. Check for foreign
objects in tread, damaged tread, mismatched tread patterns or
incorrect tire sizes. Check for bent wheels.
CENTER BEARING
Tighten drive shaft center bearing mounting bolts. If bearing
insulator is deteriorated or oil-soaked, or drive shaft can be moved
up/down in support, replace center bearing support assembly.
ENGINE & TRANSMISSION MOUNTS
Tighten mounting bolts. If rubber mounts are deteriorated or
broken, replace as needed.
DRIVE SHAFT(S)
Check drive shaft(s) for missing weights, broken welds, or
for dents affecting balance. Check for undercoating, mud, snow/ice on
drive shaft(s). Clean shafts thoroughly and test drive.
"U" JOINTS
Check for foreign material lodged in joints and flange/yokes.
Check for loose "U" joint-to-flange mounting bolts. Check for worn "U"
joint needle bearings. Check for Reddish-Brown rust-dust around "U"
joint caps. Replace "U" joints if necessary.
ADJUSTMENTS
CHECKING DRIVE SHAFT PHASING
One-Piece Drive Shafts
1) Ensure "U" joint flanges on either end of drive shaft are
in same plane. See Fig. 2. Drive shafts with slip joints between yokes
often have arrows to aid in alignment. If yokes are not in same plane,
disassemble slip joint from drive shaft splines. Install slip joint
back onto drive shaft splines, aligning "U" joint yokes. Test drive.
2) Single tube type drive shaft has slip joint on outside of
"U" joint yoke (at transmission end). If one-piece tube type drive
shaft yokes are out of alignment, the drive shaft is torque-twisted.
Drive shaft must be replaced.

1) On drive shafts greater than 30" in length, measure runout
3" from transmission flange/yoke, center bearing yoke and pinion
flange using dial indicator. Maximum runout for Ram Pickup is .030" (.
76 mm) at front and rear end of drive shaft and .035" (.89 mm) at
center of drive shaft. Maximum runout for all other models is .010" (.
25 mm) at front and rear end of drive shaft and .015" (.38 mm) at
center of drive shaft.
2) For drive shafts less than 30" in length, maximum runout
for Pickup is .030" (.76 mm). Maximum runout for all other models is .\
020" (.51 mm). Replace drive shaft if maximum runout is exceeded.
BALANCING DRIVE SHAFT
1) Perform following procedure only after inspecting all
other possible causes of vibration. See INSPECTION. Drive shaft
imbalance may often be cured by disconnecting shaft, rotating it 180
degrees and reconnecting shaft to flange. Test drive to check results.
NOTE: DO NOT run engine for prolonged periods without forced
airflow across radiator. Engine or transmission may
overheat.
2) To balance drive shaft(s), begin by raising rear wheels
off ground and turning drive shaft with engine. Balance testing may be
done by marking drive shaft in 4 positions, 90 degrees apart around
shaft. Place marks about 6" forward of rear flange/yoke weld. Number
marks 1-4.
3) Install large diameter screw-type hose clamp around drive
shaft so clamp's head is in No. 1 position. Spin drive shaft with
engine and note vibrations. If there is little or no change in
vibration intensity, move clamp head to No. 2 position, and repeat
test.
4) Continue procedure until vibration is at lowest level. If
no difference is noted with clamp head moved to all 4 positions,
vibrations may not be due to drive shaft imbalance.
5) If vibration decreases but is not completely eliminated,
place a second clamp at same position, and repeat test. Combined
weight of both clamps in one position may increase vibration. If so,
rotate clamps 1/2" apart, above and below lowest vibration level
position, and repeat test.
6) Continue to rotate clamps, as necessary, until vibration
is at lowest point. If vibration can be eliminated or reduced to
acceptable level, bend back slack end of clamp so screw cannot loosen.
If vibration level is still unacceptable, leave rear clamp(s) in
place, and repeat procedure at front end of drive shaft. Road test
vehicle. On 4WD models, perform procedure on each shaft.
CHECKING VERTICAL ANGLE
One-Piece Drive Shafts
1) Raise and support vehicle so rear wheels can be rotated.
Rotate drive shaft so a pinion flange bearing cap faces downward.
Attach Inclinometer (C-4224) magnet to bearing cap, and measure drive
shaft vertical angle. See Fig. 4. Remove inclinometer.
2) Rotate drive shaft 90 degrees until drive shaft rear yoke
bearing cap faces downward. Attach inclinometer magnet to bearing cap,
and measure drive shaft vertical angle. Difference between 2 measured
angles is drive shaft rear angle. See Fig. 5. Remove inclinometer.
3) Rotate drive shaft until a slip joint yoke bearing cap
faces downward. Attach inclinometer magnet to bearing cap, and note
angle. Remove inclinometer. Rotate drive shaft 90 degrees until drive
shaft front yoke bearing cap faces downward. Attach inclinometer
magnet to bearing cap, and note angle. Remove inclinometer.

perpendicular to each other in vertical plane. See Fig. 6. With non-
parallel or broken-back type installation, working angles of "U"
joints of given drive shaft must be equal (angle "A" = angle "B").
Fig. 6: Identifying Broken-Back Type Drive Shaft
Courtesy of Chrysler Corp.
2) Calculate by subtracting angle of output shaft center line
from angle of drive shaft. Difference should be equal to front shaft
angle subtracted from rear shaft angle.
2-Piece Drive Shafts (Except Broken-Back Type)
1) All yokes must be perpendicular in both vertical and
horizontal planes to engine crankshaft. Using Inclinometer (C-4224),
measure drive shaft vertical angles.
2) Raise and support vehicle so rear wheels can be rotated.
Rotate drive shaft so a pinion flange bearing cap faces downward.
Attach inclinometer magnet to bearing cap, and note angle. See Fig. 4.
Remove inclinometer.
3) Rotate drive shaft 90 degrees until drive shaft rear yoke
bearing cap faces downward. Attach inclinometer magnet to bearing cap,
and note angle. Difference between 2 measured angles is drive shaft
rear angle. See Fig. 5. Remove inclinometer.
4) Rotate drive shaft until a slip joint yoke bearing cap
faces downward. Attach inclinometer magnet to bearing cap, and note
angle. Remove inclinometer. Rotate drive shaft 90 degrees until drive
shaft front yoke bearing cap faces downward. Attach inclinometer
magnet to bearing cap, and note angle. Difference between 2 measured
angles is drive shaft front angle. See Fig. 5. Remove inclinometer.
5) Rotate drive shaft until front yoke of rear shaft faces
downward. Attach inclinometer magnet to bearing cap, and note angle.
Rotate drive shaft until rear yoke of front drive shaft faces
downward. Attach inclinometer magnet to bearing cap, and note angle.
Remove inclinometer.
6) Difference between 2 measured angles is drive shaft center
angle. Compare front, center and rear angles. Vertical alignment of 2
piece drive shafts at yokes should be greater than 1/2 degree and must
be retained as close to one degree as possible. See Fig. 7. If
difference of angles is greater than specified, adjustment is
necessary. See ADJUSTING VERTICAL ANGLE.