GEAR CASE
(1) Remove countershaft front bearing cap with
hammer (Fig. 40).
(2) Remove countershaft front bearing cup with
Remover 6454 and Handle C-4171 (Fig. 41).(3) Remove roll pin that secures shift lug on shift
rail in case (Fig. 42). A small pin punch can be mod-
ified by putting a slight bend in it to drive pin com-
pletely out of shift rail (Fig. 42).
(4) Remove shift lug rail.
Fig. 40 COUNTERSHAFT FRONT BEARING CAP
1 - HAMMER
2 - BEARING CAP
Fig. 41 COUNTERSHAFT FRONT BEARING CUP
1 - REMOVER
2 - HANDLE
Fig. 42 SHIFT LUG ROLL PIN
1 - PUNCH
2 - 30É BEND
3 - PIN PUNCH MODIFICATION
4 - SHIFT LUG
5 - SHIFT RAIL
DRMANUAL TRANSMISSION - NV4500 21 - 55
MANUAL TRANSMISSION - NV4500 (Continued)
(28) Remove reverse clutch gear (Fig. 62).
(29) Remove first gear from bearing and mainshaft
(Fig. 63).
(30) Remove first gear bearing from mainshaft
(Fig. 64).
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. 62 Reverse Clutch Gear
1 - REVERSE CLUTCH GEAR
Fig. 63 FIRST GEAR
1 - FIRST GEAR
Fig. 64 FIRST GEAR BEARING
1 - MAINSHAFT
2 - FIRST GEAR BEARING
21 - 62 MANUAL TRANSMISSION - NV4500DR
MANUAL TRANSMISSION - NV4500 (Continued)
the alignment dowels in the case top surface and in
the housing/adapter are tight and in good condition.
Replace the gear case or housing/adapter if cracked
or broken.
ASSEMBLY
NOTE: Gaskets are not used in the transmission.
Use Mopar Silicone Sealer or equivalent on all gear
case and extension housing sealing surfaces.
COUNTERSHAFT AND REVERSE IDLER GEAR
(1) Install countershaft front bearing cup in case
with Handle C-4171 and Installer 6061-1.
(2) Install front bearing on countershaft with
Installer C-4340 (Fig. 65).
(3) Lubricate countershaft front bearing cup and
cone with petroleum jelly.
(4) Position gear case on end with rear of case fac-
ing up (Fig. 66).
(5) Install countershaft in gear case (Fig. 66).
NOTE: Do not install rear countershaft bearing on
countershaft at this time.(6) Lubricate reverse idler gear bearings with
petroleum jelly and install first bearing and second
bearing (Fig. 67).
(7) Install idler gear front thrust washer on boss
in gear case (Fig. 67). Coat thrust washer with lib-
eral quantity of petroleum jelly to hold it in place.
Fig. 65 COUNTERSHAFT FRONT BEARING
1 - FRONT BEARING
2 - INSTALLER
3 - COUNTERSHAFT
Fig. 66 COUNTERSHAFT IN GEAR CASE
1 - GEAR CASE
2 - COUNTERSHAFT
Fig. 67 IDLER GEAR FRONT THRUST WASHER
1 - IDLER GEAR FRONT THRUST WASHER ON BOSS
DRMANUAL TRANSMISSION - NV4500 21 - 63
MANUAL TRANSMISSION - NV4500 (Continued)
(8) Install reverse idler gear in case (Fig. 68).
(9) Install idler gear rear thrust washer between
idler gear and case boss (Fig. 68).
(10) Align idler gear bearings and thrust washers
with a drift.
(11) Install reverse idler shaft with notched end of
shaft facing countershaft (Fig. 69).(12) Lift countershaft upward and position wood
block between front of shaft and case (Fig. 70).
(13) Install rear bearing cone on countershaft with
Installer C-4040 (Fig. 71).
Fig. 68 IDLER GEAR
1 - REAR THRUST WASHER
2 - REVERSE IDLER GEAR
3 - FRONT THRUST WASHER
Fig. 69 REVERSE IDLER SHAFT
1 - COUNTERSHAFT
2 - SHAFT NOTCH
3 - REVERSE IDLER SHAFT
Fig. 70 SUPPORTING COUNTERSHAFT
1 - COUNTERSHAFT
2 - WOOD BLOCK
Fig. 71 COUNTERSHAFT REAR BEARING
1 - INSTALLER
2 - REAR BEARING
3 - COUNTERSHAFT
21 - 64 MANUAL TRANSMISSION - NV4500DR
MANUAL TRANSMISSION - NV4500 (Continued)
(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. 72). Tap cup into
place with plastic mallet if necessary.
(17) Install countershaft rear bearing plate (Fig.
73).
NOTE: Verify plate is seated in notch in reverse
idler shaft before tightening bearing plate bolts.(18) Apply Mopar silicone adhesive/sealer or equiv-
alent to flange and lip of new cap. Installnewfront
bearing cap in gear case (Fig. 74) with Handle
C-4171 and Installer C-3972-A.
COUNTERSHAFT END PLAY
(1) Rotate countershaft 4-5 times to seat bearings.
(2) Mount dial indicator on case. Then position
indicator plunger on end of countershaft and zero
dial indicator (Fig. 75).
(3) Raise countershaft with screwdriver and note
end play reading on dial indicator. End play should
be 0.051 - 0.15 mm (0.002 - 0.006 in.).
Fig. 72 COUNTERSHAFT REAR BEARING CUP
1 - COUNTERSHAFT REAR BEARING CUP
Fig. 73 COUNTERSHAFT REAR BEARING PLATE
1 - COUNTERSHAFT
2 - REAR BEARING PLATE
3 - IDLER SHAFT
Fig. 74 COUNTERSHAFT FRONT BEARING CAP
1 - FRONT BEARING CAP
Fig. 75 MEASURING COUNTERSHAFT END PLAY
1 - DIAL INDICATOR
2 - COUNTER SHAFT
3 - INDICATOR MOUNTING ARM AND BASE
DRMANUAL TRANSMISSION - NV4500 21 - 65
MANUAL TRANSMISSION - NV4500 (Continued)
(4) Remove countershaft rear bearing plate.
(5) Install a end play shim that will provide mini-
mum countershaft end play. Position shim on rear
bearing cup (Fig. 76).
(6) Install countershaft rear bearing plate (Fig.
73).
NOTE: Verify plate is seated in reverse idler shaft
notch and end play shims are still in position
before installing bolts.
(7) Apply 1-2 drops Mopar Loc N' Seal or equiva-
lent to threads of rear bearing plate bolts. Then
install and tighten bearing plate bolts to 23 N´m (200
in. lbs.).
SHIFT LUG AND RAIL
(1) Lubricate shift lug and rail with CastroltSyn-
torq or equivalent.
(2) Insert shift lug rail part way into case.
(3) Install shift lug on rail.
(4) Position shift rail so roll pin notches are
toward outside of case (Fig. 77).
(5) Install roll pin that secures lug to rail (Fig. 77).
MAINSHAFT AND GEARTRAIN
CAUTION: The reverse, 1-2 and 3-4 synchro compo-
nents can be assembled and installed incorrectly.
Follow assembly procedures for component identi-
fication and location.
Lubricate mainshaft bearing surfaces and all bear-
ing assemblies with CastroltSyntorq or with petro-
leum jelly.(1) Install first snap ring in rear most groove of
mainshaft hub (Fig. 78). This snap ring locates first
gear clutch gear on shaft.
NOTE: Four of these snap rings are used to secure
various components on the mainshaft 1-2 synchro
hub. The snap rings are all the same size and are
interchangeable.
Fig. 76 COUNTERSHAFT END PLAY SHIM
1 - REAR BEARING CUP
2 - END PLAY SHIM (SELECTIVE)Fig. 77 SHIFT LUG AND RAIL
1 - NOTCHES (FOR 5TH GEAR SHIFT FORK ROLL PINS)
2 - LUG RAIL
3 - ROLL PIN HOLE
4 - SHIFT LUG
Fig. 78 FIRST GEAR BEARING AND SNAP RING
1 - SNAP RING
2 - FIRST GEAR BEARING
3 - MAINSHAFT SYNCHRO HUB
21 - 66 MANUAL TRANSMISSION - NV4500DR
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)