
(28) Remove reverse clutch gear (Fig. 63).
(29) Remove first gear from bearing and mainshaft
(Fig. 64).
(30) Remove first gear bearing from mainshaft
(Fig. 65).
CLEANING
Clean the gears, shafts, shift components and
transmission housings with a standard parts clean-
ing solvent. Do not use acid or corrosive base sol-
vents. Dry all parts except bearings with compressed
air.
Clean the shaft bearings with a mild solvent such
as Mopar degreasing solvent, Gunk or similar sol-
vents. Do not dry the bearings with compressed air.
Allow the bearings to either air dry or wipe them dry
with clean shop towels.
INSPECTION
NOTE: Minor corrosion, nicks, or pitting can be
smoothed with 400 grit emery and polished out with
crocus cloth.
Inspect the reverse idler gear, bearings, shaft and
thrust washers. Replace the bearings if the rollers
are worn, chipped, cracked, flat-spotted or brinnelled.
Replace the gear if the teeth are chipped, cracked or
worn thin.
Inspect the front bearing retainer and bearing cup.
Replace the bearing cup if scored, cracked, brinnelled
or rough. Check the release bearing slide surface of
the retainer carefully. Replace the retainer if worn or
damaged in any way.
Inspect mainshaft bearing surfaces, splines, snap
ring grooves and threads. Replace the shaft if any
surfaces exhibit considerable wear or damage.
Inspect the countershaft and bearings. Replace the
shaft if any surfaces exhibit considerable wear or
damage.
Inspect shift forks for wear and distortion. Check
fit of the sleeve in the fork to be sure the two parts
fit and work smoothly. Replace the fork if the roll pin
holes are worn oversize or damaged. Do not attempt
to salvage a worn fork. Replace shift fork roll pins if
necessary or if doubt exists about their condition.
The all bearings for wear, roughness, flat spots,
pitting or other damage. Replace the bearings if nec-
essary.
Inspect the blocker rings and fiction cones. replace
either part if worn or damaged in any way. Replace if
the friction material is burned, flaking off or worn.
Inspect synchro components wear or damage.
Replace parts if worn, cracked or distorted.
Inspect all of the thrust washers and locating pins.
Replace the pins if bent or worn. Replace the wash-
ers if worn or the locating pin notches are distorted.
Inspect the case and housing/adapter sealing and
mating surfaces are free of burrs and nicks. InspcetFig. 63 Reverse Clutch Gear
1 - REVERSE CLUTCH GEAR
Fig. 64 FIRST GEAR
1 - FIRST GEAR
Fig. 65 FIRST GEAR BEARING
1 - MAINSHAFT
2 - FIRST GEAR BEARING
21 - 60 MANUAL TRANSMISSION - NV4500DR
MANUAL TRANSMISSION - NV4500 (Continued)

(8) Install reverse idler gear in case (Fig. 69).
(9) Install idler gear rear thrust washer between
idler gear and case boss (Fig. 69).
(10) Align idler gear bearings and thrust washers
with a drift.
(11) Install reverse idler shaft with notched end of
shaft facing countershaft (Fig. 70).
(12) Lift countershaft upward and position wood
block between front of shaft and case (Fig. 71).
(13) Install rear bearing cone on countershaft with
Installer C-4040 (Fig. 72).
(14) Remove wood block from under countershaft
and lower countershaft front bearing into front bear-
ing cup.(15) Lubricate countershaft rear bearing cup and
cone with petroleum jelly.
(16) Install countershaft rear bearing cup in gear
case and over rear bearing (Fig. 73). Tap cup into
place with plastic mallet if necessary.
(17) Install countershaft rear bearing plate (Fig.
74).
NOTE: Verify plate is seated in notch in reverse
idler shaft before tightening bearing plate bolts.
Fig. 69 IDLER GEAR
1 - REAR THRUST WASHER
2 - REVERSE IDLER GEAR
3 - FRONT THRUST WASHER
Fig. 70 REVERSE IDLER SHAFT
1 - COUNTERSHAFT
2 - SHAFT NOTCH
3 - REVERSE IDLER SHAFT
Fig. 71 SUPPORTING COUNTERSHAFT
1 - COUNTERSHAFT
2 - WOOD BLOCK
Fig. 72 COUNTERSHAFT REAR BEARING
1 - INSTALLER
2 - REAR BEARING
3 - COUNTERSHAFT
21 - 62 MANUAL TRANSMISSION - NV4500DR
MANUAL TRANSMISSION - NV4500 (Continued)

(3) Install snap ring on mainshaft 1-2 synchro hub
to secure clutch cone (Fig. 81). 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. 82).
(b) Place wood blocks under hub that will raise
hub about 3.5 cm (1.375 in.) above surface of work-
bench. Then allow sleeve to drop down on hub (Fig.
83).
(c) Install springs and struts in hub (Fig. 83).
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 pro-
ceeding.
(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. 81 FIRST GEAR CLUTCH CONE SNAP RING
1 - FIRST GEAR CLUTCH CONE
2 - MAINSHAFT 1-2 SYNCHRO HUB
3 - CLUTCH CONE SNAP RING
Fig. 82 1-2 SYNCHRO SLEEVE ON HUB
1 - ALIGN WIDE SLOT IN SLEEVE WITH WIDE SPLINE OF HUB
2 - 1-2 SLEEVE AND HUB
Fig. 83 1-2 SYNCHRO STRUTS AND SPRINGS
1 - WOOD BLOCKS
2 - HUB
3 - SLEEVE
4 - STRUTS AND SPRINGS (4 EACH)
DRMANUAL TRANSMISSION - NV4500 21 - 65
MANUAL TRANSMISSION - NV4500 (Continued)

(42) Set transmission case upright (Fig. 109).
(43) Install drive gear thrust bearing on mainshaft
(Fig. 110). 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. 111).
(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. 112).
Fig. 109 MAINSHAFT AND GEARTRAIN IN CASE
1 - MAINSHAFT AND GEARTRAIN
2 - FOURTH SPEED CLUTCH GEAR
Fig. 110 DRIVE GEAR THRUST BEARING
1 - MAINSHAFT
2 - DRIVE GEAR THRUST BEARING
Fig. 111 FRONT BEARING ON DRIVE GEAR
1 - INSTALLER
2 - BEARING
3 - DRIVE GEAR
Fig. 112 FRONT BEARING CUP IN RETAINER
1 - INSTALLER
2 - HANDLE
3 - WOOD BLOCKS
4 - RETAINER
21 - 72 MANUAL TRANSMISSION - NV4500DR
MANUAL TRANSMISSION - NV4500 (Continued)

(5) Install new oil seal in front bearing retainer
with Installer 6052 (Fig. 113). Use one or two wood
blocks to support retainer as shown. Lubricate seal
lip with petroleum jelly after installation.
(6) Clean contact surfaces of gear case and front
bearing retainer with a wax and grease remover.
(7) Apply Mopar Silicone Sealer or equivalent to
flange surface of front bearing retainer (Fig. 114).
(8) Install front bearing retainer over drive gear
and start it into case.
(9) Start front bearing retainer in gear case. Verify
retainer lube channel is at the top-center(12
O'clock)position (Fig. 114).(10) Align front bearing retainer bolt holes and tap
retainer into place with plastic mallet. Installnew
retainer bolts and tighten to 30 N´m (22 ft. lbs.) (Fig.
115).
NOTE: Never reuse the old bolts.
MAINSHAFT END PLAY
(1) Install mainshaft rear bearing cup in case and
over bearing. Tap bearing cup into place with plastic
mallet.
(2) Install rear bearing plate to hold mainshaft
and rear bearing in position (Fig. 116).
NOTE: Do not install any end play shims at this
time.
(3) Tighten rear bearing plate bolts securely.
(4) Place gear case in upright position on bench.
Either cut hole in bench to accept drive gear and
front retainer or use C-clamps to secure transmission
on bench.
NOTE: Do not leave transmission unsupported.
(5) Install Extension Rod 8161 into a suitable
threaded hole in rear of case.
(6) Mount dial indicator on extension rod and posi-
tion indicator plunger against end of mainshaft.
(7) Move mainshaft forward to remove all play
then zero dial indicator.
(8) Move mainshaft upward and record dial indica-
tor reading. Move mainshaft with pry tool positioned
between drive gear and case.
(9) End play should be 0.051-0.15 mm (0.002-0.006
in.). Select fit shims are available to adjust end play.
If end play adjustment is required, remove bearing
plate and install necessary shim.
(10) Reinstall rear bearing plate with oil hole in
bearing plate at the top (Fig. 116).
(11) Apply Mopar Lock N' Seal or equivalent to
bearing plate bolt threads. Install and tighten bolts
to 23 N´m (200 in. lbs.).
Fig. 113 BEARING RETAINER OIL SEAL
1 - INSTALLER
2 - RETAINER
3 - WOOD BLOCK
Fig. 114 LOCATION OF FRONT RETAINER LUBE
CHANNEL
1 - LUBE CHANNEL
2 - FRONT RETAINER
3 - APPLY GASKET MAKER HERE
Fig. 115 FRONT BEARING RETAINER
1 - DRIVE GEAR
2 - FRONT BEARING RETAINER
DRMANUAL TRANSMISSION - NV4500 21 - 73
MANUAL TRANSMISSION - NV4500 (Continued)

(8) Assemble and install fifth synchro clutch gear
and stop ring in fifth gear hub (Fig. 125). Verify
parts are seated in fifth gear hub.
(9) Install clutch gear snap ring (Fig. 126).
(10) Align roll pin holes in shift fork with notches
in shift lug rail. Then install roll pins from top side
of fork (Fig. 123).
NOTE: Roll pins only fit one way due to small
shoulder at one end of each pin.
FIFTH GEAR NUT
(1) Install belleville washer onto the mainshaft.
(2) Install fifth gear nut over the mainshaft.
(3) Tighten the clamp bolt until the gap in the
clamp nut assembly is closed.
(4) Back the clamp bolt off one full turn.(5) Place 10-15 drops of Loctite 272 onto the main-
shaft threads where the fifth gear nut will be
engaged.
(6) Install fifth gear nut on mainshaft (Fig. 127).
(7) Hold mainshaft Socket 6993 4X2 or Socket
6984 4X4 while installing the fifth gear nut.
(8) Tighten fifth gear nut as much as possible with
Wrench 6743, long handle ratchet, breaker bar and
applicable socket wrench (Fig. 128).
(9) Lock mainshaft gears by shifting all synchro
sleeves into engaged position.
Fig. 125 FIFTH SYNCHRO CLUTCH GEAR AND
STOP RING
1 - STOP RING
2 - CLUTCH GEAR
Fig. 126 FIFTH SYNCHRO CLUTCH SNAP RING
1 - CLUTCH GEAR RING
2 - FIFTH SYNCHRO CLUTCH GEAR
Fig. 127 FIFTH GEAR NUT
1 - FIFTH GEAR
2 - FIFTH GEAR NUT
Fig. 128 FIFTH GEAR NUT
1 - WRENCH
2 - FIFTH GEAR NUT
3 - SOCKET
21 - 76 MANUAL TRANSMISSION - NV4500DR
MANUAL TRANSMISSION - NV4500 (Continued)

(10) Tighten fifth gear nut with Nut Wrench 6743
and high capacity torque wrench. Tighten nut to 366-
380 N´m (270-280 ft. lbs.). Have helper hold trans-
mission steady if necessary.
(11) Torque the fifth gear clamp nut clamping bolt
to 13.5 N´m (10 ft. lbs.).
(12) Unlock the mainshaft gears by shifting all
synchro sleeves out of the engaged position.
EXTENSION/ADAPTER HOUSING
(1) Clean mating surfaces of extension/adapter
housing and gear case with a wax and grease
remover.
(2) Check alignment dowels in gear case and hous-
ing or adapter. Be sure dowels are in position and
seated.
(3) Apply Mopar Silicone Sealer or equivalent to
gear case and housing mating surfaces.
(4) Align and install extension/adapter housing on
gear case (Fig. 129).
(5) Apply Mopar Lock N' Seal or equivalent to
threads of extension/adapter housing bolts.
(6) Install and tighten housing bolts to 54 N´m (40
ft. lbs.).
SHIFT MECHANISM
(1) Clean mating surfaces of shift cover and gear
case with wax and grease remover.
(2) Apply a small amount of Mopar silicone sealer
or equivalent to sealing surface of shift cover.
CAUTION: Do not over-apply an excesive amount
sealer. Excess can squeezed into gear case and
could block lubricant feed holes in time.(3) Lubricate synchro sleeves with CastroltSyn-
torq gear lubricant or equivalent. Then apply light
coat of petroleum jelly to shift fork contact surfaces.
(4) Verify shift fork pads (Fig. 130) are secure.
(5) Verify 1-2 and 3-4 synchro sleeves and forks in
shift cover are in neutral position.
(6) Align and seat shift cover on transmission.
NOTE: If cover will not seat, it may not be aligned
on gear case dowels or shift forks are not aligned
with sleeves and shift lug.
(7) Apply Mopar Lock N' Seal or equivalent to
threads of shift cover bolts.
(8) Install shift cover bolts and tighten to 27-31
N´m (216-276 in. lbs.).
(9) Apply sealer to backup lamp switch. Install
switch into cover and tighten to 22-34 N´m (193-265
in. lbs.).
(10) Install vent assembly if removed. Apply an
adhesive/sealer to vent tube to help secure it in cover.
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.
Fig. 129 INSTALLING EXTENSION/ADAPTER
HOUSING
1 - GEAR CASE
2 - EXTENSION HOUSING
Fig. 130 SHIFT FORK PAD
1 - SHIFT FORK PADS
2 - FIFTH-REVERSE FORK
DRMANUAL TRANSMISSION - NV4500 21 - 77
MANUAL TRANSMISSION - NV4500 (Continued)

FIFTH-REVERSE SHIFT FORK PADS
Three shift pads on the forks are held in place by
tension and a small locating tang (Fig. 138).
To remove the pads, grasp a pad with hand and tilt
it out and off the fork. If pad is difficult to remove by
hand, insert a screwdriver blade between the pad
and fork and pry the pad off.
EXPANSION PLUG
The expansion plugs at the rear of the shift rail
bores (Fig. 139) can be replaced if loose/leaking.
(1) Drill 6 mm (1/4 in.) diameter hole in center of
the plug to be removed.
(2) Pry plug out of cover with tapered punch.
(3) Clean all chips from shift cover and plug bores.
Then clean plug bores with solvent and dry with
clean shop towel.
INSTALLATION
EXPANSION PLUG
(1) Apply small bead of Mopar silicone sealer or
equivalent to outer edge of each new plug.
(2) Position each plug in bore and tap into place
with hammer and punch or socket.
FIFTH-REVERSE SHIFT FORK PADS
(1) Align pad locating tab.
(2) Snap pads into place and verify locating tabs
are locked-in.
SHIFT COVER
(1) Clean mating surfaces of shift mechanism
cover and gear case with wax and grease remover.
(2) Apply a small amount of Mopar silicone sealer
or equivalent to sealing surface of shift mechanism
cover.
CAUTION: Do not use an excessive amount sealer.
Excess can squeezed into gear case and could
block lubricant feed holes in time.
(3) Lubricate synchro sleeves with CastroltSyn-
torq gear lubricant or equivalent. Then apply light
coat of petroleum jelly to shift fork contact surfaces.
(4) Verify shift fork pads (Fig. 140) are secure.
(5) Verify 1-2 and 3-4 synchro sleeves and forks in
shift cover are in neutral position.
(6) Align and seat shift mechanism cover on trans-
mission.
NOTE: If cover will not seat, it may not be aligned
on gear case dowels or shift forks are not aligned
with sleeves and shift lug.
Fig. 138 SHIFT FORK PAD LOCATIONS
1 - SHIFT FORK PADS
2 - FIFTH-REVERSE FORK
Fig. 139 EXPANSION PLUG LOCATION
1 - EXPANSION PLUGSFig. 140 SHIFT FORK PAD
1 - SHIFT FORK PADS
2 - FIFTH-REVERSE FORK
DRMANUAL TRANSMISSION - NV4500 21 - 85
SHIFT MECHANISM (Continued)