1998 DODGE RAM 1500 FRONT HUB

(10) Remove second gear clutch cone snap ring
from mainshaft synchro hub groove (Fig. 50).
(11) Remove second gear clutch cone, synchro
clutch ring and synchro stop ring (Fig. 51).(12) Remove 1-2 synchro hub snap ring (Fig. 52).
(13) Remove 1-2 synchro sleeve, hub, struts and
springs as an assembly (Fig. 53).
NOTE: Tapered side of sleeve also goes toward
front. Do not disassemble synchro components
unless worn or damaged.
Fig. 50 SECOND GEAR CLUTCH CONE SNAP RING
1 - 1-2 SLEEVE
2 - SNAP RING
3 - SECOND GEAR CLUTCH CONE
Fig. 51 SECOND GEAR CLUTCH CONE AND RING
1 - 1-2 SLEEVE AND HUB
2 - SYNCHRO STOP RING
3 - CLUTCH RING
4 - SECOND GEAR CLUTCH CONE
Fig. 52 1-2 SLEEVE AND HUB SNAP RING
1 - 1-2 HUB SNAP RING
2 - 1-2 SLEEVE AND HUB
Fig. 53 1-2 SYNCHRO SLEEVE AND HUB
1 - 1-2 SLEEVE AND HUB
21 - 58 MANUAL TRANSMISSION - NV4500DR
MANUAL TRANSMISSION - NV4500 (Continued)

(14) Remove first gear synchro stop ring and
clutch ring (Fig. 54).
(15) Remove first gear clutch cone front snap ring
from mainshaft hub (Fig. 55).(16) Remove first gear clutch cone (Fig. 56).
(17) Remove first gear clutch gear rear snap ring
from mainshaft hub (Fig. 56).
NOTE: Do not remove this snap ring unless main-
shaft is being replaced.
Fig. 54 FIRST GEAR STOP AND CLUTCH RING
1 - FIRST GEAR CLUTCH RING
2 - FIRST GEAR STOP RING
Fig. 55 FIRST GEAR CLUTCH GEAR FRONT SNAP
RING
1 - FIRST SPEED CLUTCH GEAR
2 - CLUTCH GEAR SNAP RING (FRONT)
Fig. 56 FIRST GEAR CLUTCH GEAR
1 - CLUTCH GEAR SNAP RING (REAR)
2 - FIRST SPEED CLUTCH GEAR
DRMANUAL TRANSMISSION - NV4500 21 - 59
MANUAL TRANSMISSION - NV4500 (Continued)

(2) Install first gear clutch cone on mainshaft 1-2
synchro hub with recessed side of cone facing front
(Fig. 79). Verify cone is seated against snap ring on
hub.
(3) Install snap ring on mainshaft 1-2 synchro hub
to secure clutch cone (Fig. 80). Verify snap ring is
seated in hub groove and against clutch cone.
(4) Support mainshaft in upright position to install
remaining gears, snap rings and synchro compo-
nents. Shaft can be supported in gear case or hole
can be cut in workbench to support shaft.
(5) If 1-2 synchro hub and sleeve were disassem-
bled for service, reassemble hub, sleeve, struts and
springs as follows:(a) Align and install sleeve on hub. Rotate sleeve
until it slides onto hub. Sleeve only fits one way
and will easily slide onto hub when long slot in
sleeve, aligns with long shoulder on hub (Fig. 81).
(b)
Place wood blocks under hub that will raise hub
about 3.5 cm (1.375 in.) above surface of workbench.
Then allow sleeve to drop down on hub (Fig. 82).
(c)Install springs and struts in hub (Fig. 82). Use
lots of petroleum jelly to hold them in place. Then
compress struts with your fingers and move sleeve
upward until struts are started in sleeve. Verify that
struts are engaged in sleeve before proceeding.
(d) Turn synchro assembly upright. Then move
sleeve into neutral position on hub and work struts
into sleeve at same time. Be sure struts are seated
and springs are not displaced during assembly.
Fig. 79 FIRST GEAR CLUTCH CONE
1 - MAINSHAFT 1-2 SYNCHRO HUB
2 - FIRST GEAR CLUTCH CONE
Fig. 80 FIRST GEAR CLUTCH CONE SNAP RING
1 - FIRST GEAR CLUTCH CONE
2 - MAINSHAFT 1-2 SYNCHRO HUB
3 - CLUTCH CONE SNAP RING
Fig. 81 1-2 SYNCHRO SLEEVE ON HUB
1 - ALIGN WIDE SLOT IN SLEEVE WITH WIDE SPLINE OF HUB
2 - 1-2 SLEEVE AND HUB
Fig. 82 1-2 SYNCHRO STRUTS AND SPRINGS
1 - WOOD BLOCKS
2 - HUB
3 - SLEEVE
4 - STRUTS AND SPRINGS (4 EACH)
DRMANUAL TRANSMISSION - NV4500 21 - 67
MANUAL TRANSMISSION - NV4500 (Continued)

(20) Install synchro stop ring on third gear (Fig.
96). Verify stop ring is seated on cone taper.
(21) If 3-4 synchro was disassembled for service,
reassemble synchro components as follows:
(a) Align and install synchro sleeve on hub (Fig.
97).Front side of hub has a narrow groove
machined in it.
(b) Insert all three synchro struts in slots
machined in sleeve and hub (Fig. 97).
(c) Install and seat synchro springs (Fig. 97).
Use screwdriver to compress springs and seat them
in struts and hub as shown.(22) Start 3-4 synchro assembly on mainshaft with
the hub groove and sleeve groove both facing for-
ward. Tap assembly onto shaft splines until hub is
about 3 mm (0.125 in.) away from third gear stop
ring. Then align stop ring with synchro sleeve and
hub and seat synchro assembly with Installer C-4040
(Fig. 98).
(23) Verify 3-4 synchro hub is seated on shaft with
approximately 3 mm (0.125 in.) of shaft spline visi-
ble.
NOTE: If hub is not seated, stop ring lugs are mis-
aligned. Rotate ring until lugs are engaged in 3-4
hub slots.
(24) Verify that second and third gear rotate freely
at this point. If not, determine the cause and correct.
(25) Invert mainshaft in case or bench.
(26) Install first gear bearing on mainshaft.
(27) Install first gear on shaft with clutch hub side
of gear facing the front of shaft (Fig. 99). Verify tabs
on clutch ring are aligned and seated in first gear
hub.
NOTE: 1-2 synchro hub will not seat properly if
clutch ring tabs are misaligned.
Fig. 96 THIRD GEAR STOP RING
1 - SYNCHRO STOP RING
2 - THIRD GEAR
Fig. 97 SYNCHRO ASSEMBLY (3-4)
1 - STRUT (3)
2 - SPRING (3)
3 - 3-4 SLEEVE
4 - 3-4 HUB
Fig. 98 SEATING 3-4 SYNCHRO ASSEMBLY ON
MAINSHAFT
1 - 3-4 SYNCHRO HUB
2 - HUB GROOVE
3 - INSTALLER C-4040
DRMANUAL TRANSMISSION - NV4500 21 - 71
MANUAL TRANSMISSION - NV4500 (Continued)

(39) Roll gear case onto its left side.
(40) Grip mainshaft at pilot bearing hub and just
behind reverse gear. Then lift assembly and guide
rear of shaft through bearing bore at rear of case.
(41) Continue holding front of shaft but switch
grip at rear to shaft output splines. Lift mainshaft
assembly slightly, align gears and seat assembly in
case.
(42) Set transmission case upright (Fig. 108).
(43) Install drive gear thrust bearing on mainshaft
(Fig. 109). Use plenty of petroleum jelly to hold bear-
ing in place.
(44) Check alignment and mesh of mainshaft
gears. If gears are not aligned, roll case on side and
realign shaft and gears in case.DRIVE GEAR AND RETAINER
(1) Install bearing on drive gear with Installer
6448 (Fig. 110).
(2) Lubricate pilot bearing with petroleum jelly
and install it in drive gear bore.
(3) Install drive gear on mainshaft. Work gear
rearward until mainshaft hub is seated in pilot bear-
ing.
(4) Install bearing cup in front retainer with Han-
dle C-4171 and Installer C-4308 (Fig. 111).
Fig. 108 MAINSHAFT AND GEARTRAIN IN CASE
1 - MAINSHAFT AND GEARTRAIN
2 - FOURTH SPEED CLUTCH GEAR
Fig. 109 DRIVE GEAR THRUST BEARING
1 - MAINSHAFT
2 - DRIVE GEAR THRUST BEARING
Fig. 110 FRONT BEARING ON DRIVE GEAR
1 - INSTALLER
2 - BEARING
3 - DRIVE GEAR
Fig. 111 FRONT BEARING CUP IN RETAINER
1 - INSTALLER
2 - HANDLE
3 - WOOD BLOCKS
4 - RETAINER
21 - 74 MANUAL TRANSMISSION - NV4500DR
MANUAL TRANSMISSION - NV4500 (Continued)

(4) Install synchro sleeve on hub of countershaft
fifth gear with tapered side of sleeve facing front and
the flat side facing rear (Fig. 120).
(5) Install shift fork in synchro sleeve (Fig. 121).(6) Install assembled fifth gear, synchro sleeve and
shift fork (Fig. 122). Align fork with shift lug rail and
align gear with bearings and countershaft. Start
components onto shaft and rail, then tap gear and
fork into place with plastic or rawhide mallet.
(7) Install fifth gear synchro struts and springs
(Fig. 123).
Fig. 120 SYNCHRO SLEEVE ON COUNTERSHAFT
FIFTH
1 - GEAR HUB
2 - SYNCHRO SLEEVE
3 - COUNTERSHAFT FIFTH GEAR
Fig. 121 FIFTH GEAR SHIFT FORK IN SYNCHRO
SLEEVE
1 - SYNCHRO SLEEVE
2 - SHIFT FORK
Fig. 122 COUNTERSHAFT FIFTH GEAR, SHIFT
FORK AND SYNCHRO SLEEVE
1 - SHIFT FORK AND SLEEVE
2 - FIFTH GEAR HUB
3 - SHIFT FORK ROLL PINS
Fig. 123 FIFTH GEAR SYNCHRO STRUTS AND
SPRINGS
1 - FIFTH GEAR HUB
2 - SYNCHRO SPRING (3)
3 - SYNCHRO STRUT (3)
DRMANUAL TRANSMISSION - NV4500 21 - 77
MANUAL TRANSMISSION - NV4500 (Continued)

INSTALLATION
NOTE: If a new transmission is being installed, use all
components supplied with the new transmission. For
example, if a new shift tower is supplied with the new
transmission, do not re-use the original shift tower.
(1) Apply light coat of Mopar high temperature
bearing grease or equivalent to contact surfaces of
the following components:
²input shaft splines.
²release bearing slide surface of front retainer.
²release bearing bore.
²release fork.
²release fork ball stud.
²propeller shaft slip yoke.
(2) Apply sealer to threads of bottom PTO cover
bolt and install bolt in case.
(3) Mount transmission on jack and position trans-
mission under vehicle.
(4) Raise transmission until input shaft is centered
in release bearing and clutch disc hub.
(5)
Move transmission forward and start input shaft
in release bearing, clutch disc and pilot bushing.
(6)Work transmission forward until seated against
clutch housing. Do not allow transmission to remain
unsupported after input shaft has entered clutch disc.
(7) Install transmission bolts and tighten to 108
N´m (80 ft. lbs.).
(8) Install transmission mount on transmission or
rear crossmember.
(9) Install rear crossmember.
(10) Remove transmission jack and engine support
fixture.
(11) Position transmission harness wires in clips
on shift cover.
(12) Install clutch slave cylinder and install slave
cylinder shield, if equipped.
(13) Connect speed sensor and backup light switch
wires.
TWO WHEEL DRIVE
(1) Fill transmission with recommended lubricant.
Correct fill level is bottom edge of fill plug hole.
(2) Align and install propeller shaft.
(3) Lower vehicle.
(4) Clean the mating surfaces of shift tower, isola-
tor plate and shift cover with suitable wax and
grease remover.
(5) Apply Mopar Gasket Maker or equivalent to
the sealing surface of the shift cover. Do not over
apply sealant.
(6) Install the isolator plate onto the shift cover,
metal side down.
(7) Install the shift tower onto the isolator plate.
No sealant is necessary between the shift tower and
the isolator plate.(8) Verify that the shift tower, isolator plate and
the shift tower bushings are properly aligned.
(9) Install the bolts to hold the shift tower to the
isolator plate and the shift cover. Tighten the shift
tower bolts to 10.2-11.25 N´m (7.5-8.3 ft. lbs.).
(10) Install the shift lever extension onto the shift
tower and lever assembly.
(11) Install shift boot and bezel.
(12) Connect battery negative cable.
FOUR WHEEL DRIVE
(1) Install transfer case shift mechanism on trans-
mission.
(2) Install transfer case on transmission jack.
Secure transfer case to jack with safety chains.
(3) Raise jack and align transfer case input gear
with transmission mainshaft.
(4) Move transfer case forward and seat it on
adapter.
(5) Install transfer case nuts and tighten to:
²If 3/8 studs 41-47 N´m (30-35 ft. lbs.).
²If 5/16 studs 30-41 N´m (22-30 ft. lbs.).
(6) Install transfer case shift mechanism to side of
transfer case.
(7) Connect transfer case shift lever to range lever
on transfer case.
(8) Align and connect propeller shafts.
(9) Fill transmission with required lubricant.
Check lubricant level in transfer case and add lubri-
cant if necessary.
(10) Install transfer case skid plate, if equipped
and crossmember. Tighten attaching bolts/nuts to 41
N´m (30 ft. lbs.).
(11) Install exhaust system components.
(12) Lower vehicle.
(13) Clean the mating surfaces of shift tower, iso-
lator plate and shift cover with suitable wax and
grease remover.
(14) Apply Mopar Gasket Maker or equivalent to
the sealing surface of the shift cover. Do not over
apply sealant.
(15) Install the isolator plate onto the shift cover,
metal side down.
(16) Install the shift tower onto the isolator plate.
No sealant is necessary between the shift tower and
the isolator plate.
(17) Verify that the shift tower, isolator plate and
the shift tower bushings are properly aligned.
(18) Install the bolts to hold the shift tower to the
isolator plate and the shift cover. Tighten the shift
tower bolts to 10.2-11.25 N´m (7.5-8.3 ft. lbs.).
(19) Install the shift lever extension onto the shift
tower and lever assembly.
(20) Install shift lever boot and bezel.
(21) Connect battery negative cable.
21 - 80 MANUAL TRANSMISSION - NV4500DR
MANUAL TRANSMISSION - NV4500 (Continued)

IDENTIFICATION
The transmission has two identification tags
attached to the driver side upper clutch housing (Fig.
2). One tag provides the transmission part number.
The second tag provides sequencing and build date
information. The information on the tags are essen-
tial to correct parts ordering.
OPERATION
The driver selects a particular gear by moving the
shift lever to the desired gear position. As the shift
lever moves the selected shift rail, the shift fork
attached to that rail begins to move. The fork is posi-
tioned in a groove in the outer circumference of the
synchronizer sleeve. As the shift fork moves the syn-
chronizer sleeve, the synchronizer begins to speed-up
or slow down the selected gear (depending on
whether we are up-shifting or down-shifting). The
synchronizer does this by having the synchronizer
hub splined to the mainshaft or the countershaft in
some cases, and moving the blocker ring into contact
with the gear's friction cone. As the blocker ring and
friction cone come together, the gear speed is brought
up or down to the speed of the synchronizer. As the
two speeds match, the splines on the inside of the
synchronizer sleeve become aligned with the teeth on
the blocker ring and friction cone and eventually will
slide over the teeth, locking the gear to the main-
shaft or countershaft through the synchronizer.
DIAGNOSIS AND TESTING
LOW LUBRICANT LEVEL
A low transmission lubricant level is generally the
result of a leak, inadequate lubricant fill or an incor-
rect lubricant level check. A correct lubricant level
check can only be made when the vehicle is level.
Also allow the lubricant to settle for a minute or sobefore checking. These recommendations will ensure
an accurate check and avoid an underfill or overfill
condition. Always check the lubricant level after any
addition of fluid to avoid an incorrect lubricant level
condition.
Leaks can occur at the mating surfaces of the gear
case, adaptor or extension housing, or from the front/
rear seals. A suspected leak could also be the result
of an overfill condition. Leaks at the rear of the
extension or adapter housing will be from the hous-
ing oil seals. Leaks at component mating surfaces
will probably be the result of inadequate sealer, gaps
in the sealer, incorrect bolt tightening or use of a
non-recommended sealer. A leak at the front of the
transmission will be from either the front bearing
retainer or retainer seal. Lubricant may be seen drip-
ping from the clutch housing after extended opera-
tion. If the leak is severe, it may also contaminate
the clutch disc causing the disc to slip, grab and or
chatter.
HARD SHIFTING
Hard shifting is usually caused by a low lubricant
level, improper or contaminated lubricants. The con-
sequence of using non-recommended lubricants is
noise, excessive wear, internal bind and hard shift-
ing. Substantial lubricant leaks can result in gear,
shift rail, synchro, and bearing damage. If a leak
goes undetected for an extended period, the first indi-
cations of component damage are usually hard shift-
ing and noise.
Component damage, incorrect clutch adjustment or
damaged clutch pressure plate or disc are additional
probable causes of increased shift effort. Incorrect
adjustment or a worn/damaged pressure plate or disc
can cause incorrect release. If clutch problem is
advanced, gear clash during shifts can result. Worn
or damaged synchro rings can cause gear clash when
shifting into any forward gear. In some new or
rebuilt transmissions, new synchro rings may tend to
stick slightly causing hard or noisy shifts. In most
cases this condition will decline as the rings wear-in.
TRANSMISSION NOISE
Most manual transmissions make some noise dur-
ing normal operation. Rotating gears generate a mild
whine that is audible, but generally only at extreme
speeds. Severe highly audible transmission noise is
generally the initial indicator of a lubricant problem.
Insufficient, improper or contaminated lubricant
will promote rapid wear of gears, synchros, shift
rails, forks and bearings. The overheating caused by
a lubricant problem, can also lead to gear breakage.
REMOVAL
(1) Shift transmission into Neutral.
Fig. 2 IDENTIFICATION TAG LOCATION
1 - IDENTIFICATION TAGS
21 - 90 MANUAL TRANSMISSION - NV5600DR
MANUAL TRANSMISSION - NV5600 (Continued)