TRANSMISSION AND TRANSFER CASE
TABLE OF CONTENTS
page page
MANUAL TRANSMISSION - NV3500..........1
MANUAL TRANSMISSION - NV4500..........43
MANUAL TRANSMISSION - NV5600..........88
AUTOMATIC TRANSMISSION - 48RE........130
AUTOMATIC TRANSMISSION - 45RFE/545RFE.311
TRANSFER CASE - NV241 GENII...........415TRANSFER CASE - NV271................447
TRANSFER CASE - NV243................482
TRANSFER CASE - NV244 GENII...........512
TRANSFER CASE - NV273................542
MANUAL TRANSMISSION - NV3500
TABLE OF CONTENTS
page page
MANUAL TRANSMISSION - NV3500
DESCRIPTION..........................1
OPERATION............................1
DIAGNOSIS AND TESTING................3
REMOVAL.............................3
DISASSEMBLY..........................4CLEANING............................15
INSPECTION..........................16
ASSEMBLY............................17
INSTALLATION.........................39
SPECIFICATIONS.......................40
SPECIAL TOOLS.......................40
MANUAL TRANSMISSION -
NV3500
DESCRIPTION
The transmission is a medium-duty 5-speed, con-
stant mesh fully synchronized manual transmission
with fifth gear overdrive range. The transmission is
available in two and four-wheel drive configurations.
The transmission gear case consists of two aluminum
housings (Fig. 1). The clutch housing is an integral
part of the transmission front housing.
A combination of roller and ball bearings are used
to support the transmission shafts in the two hous-
ings. The transmission gears all rotate on caged type
needle bearings. A roller bearing is used between the
input and output shaft.
The transmission has a single shaft shift mecha-
nism with three shift forks all mounted on the shaft.
The shaft is supported in the front and rear housings
by bushings and one linear ball bearing. Internal
shift components consist of the forks, shaft, shift
lever socket and detent components
OPERATION
The manual transmission receives power through the
clutch assembly from the engine. The clutch disc issplined to the transmission input shaft and is turned at
engine speed at all times that the clutch is engaged.
The input shaft is connected to the transmission coun-
tershaft through the mesh of fourth speed gear on the
input shaft and the fourth countershaft gear. At this
point, all the transmission gears are spinning.
The driver selects a particular gear by moving the
shift lever to the desired gear position. This movement
moves the internal transmission shift components to
begin the shift sequence. As the shift lever moves the
selected shift rail, the shift fork attached to that rail
begins to move. The fork is positioned in a groove in the
outer circumference of the synchronizer sleeve. As the
shift fork moves the synchronizer sleeve, the synchro-
nizer begins to speed-up or slow down the selected gear
(depending on whether we are up-shifting or down-shift-
ing). The synchronizer does this by having the synchro-
nizer hub splined to the mainshaft 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 the friction cone
and eventually will slide over the teeth, locking the gear
to the mainshaft, or countershaft, through the synchro-
nizer.
DRTRANSMISSION AND TRANSFER CASE 21 - 1
Inspect output shaft bearing retainer, the
U-shaped retainer must be flat and free of distortion.
Replace the retainer if the threads are damaged or if
the retainer is bent or cracked.
COUNTERSHAFT BEARINGS AND RACES
The countershaft bearings and races are machine
lapped during manufacture to form matched sets.
The bearings and races should not be interchanged.
NOTE: The bearing races are a permanent press fit
in the housings and are NOT serviceable. If a bear-
ing race becomes damaged, the front or rear hous-
ing must be replaced. A new countershaft bearing
will be supplied with each new housing for service
use.
REVERSE IDLER COMPONENTS
Inspect the idler gear, bearing, shaft, thrust
washer, wave washer and thrust plate. Replace the
bearing if any of the needle bearing rollers are worn,
chipped, cracked, flat-spotted or brinnelled. Also
replace the bearing if the plastic bearing cage is
damaged or distorted.
Replace thrust washer, wave washer or thrust
plate if cracked, chipped or worn. Replace idler gear
if the teeth are chipped, cracked or worn thin.
Replace shaft if worn, scored or the bolt threads are
damaged beyond repair. Replace support segment if
cracked or chipped and replace the idler attaching
bolts if the threads are damaged.
Shift Socket
Inspect the shift socket for wear or damage.
Replace the socket if the roll pin or shift shaft bores
are damaged. Minor nicks in the shift lever ball seat
in the socket can be smoothed down with 400 grit
emery or wet/dry paper. Replace the socket if the ball
seat is worn or cracked. Do not reuse the original
shift socket roll pin. Install anewpin during assem-
bly. The socket roll pin is approximately 33 mm
(1-1/4 in.) long.
Output Shaft And Geartrain
Inspect all gears for worn, cracked, chipped or bro-
ken teeth. Also check condition of the bearing bore in
each gear. The bores should be smooth and free of
surface damage. Discoloration of the gear bores is a
normal occurrence and is not a reason for replace-
ment. Replace gears only when tooth damage has
occurred or if the bores are brinnelled or severely
scored.
Inspect the shaft splines and bearings surfaces.
Minor nicks on the bearing surfaces can be smoothed
with 320/420 grit emery and final polished with cro-
cus cloth. Replace the shaft if the splines are dam-aged or bearing surfaces are deeply scored, worn or
brinnelled.
ASSEMBLY
NOTE: Sealers are used at all case joints. Use
Mopar Gasket Maker or equivalent for all case joints
and Mopar silicone sealer or equivalent for the
input shaft bearing retainer.
SYNCHRONIZER
(1) Slide sleeve onto the hub, leaving enough room
to install the spring in the hub and strut in the hub
groove.
(2) Install first spring in the hub, then install a
strut over the spring. Verify spring is seated in the
spring bore in the strut.
(3) Slide sleeve onto the hub far enough to hold
the first strut and spring in place.
(4) Place detent ball in the top of the strut, then
press the ball into place with a small screwdriver.
Work the sleeve over the ball to hold it in place.
(5) Repeat procedure for the remaining springs,
struts and balls. Use tape or rubber bands to tempo-
rarily secure each strut and ball as they are
installed.
(6) Verify the synchro three springs, struts and
detent balls are all in place (Fig. 49).
Fig. 49 SYNCHRONIZER COMPONENTS
1 - SLEEVE
2 - HUB SHOULDER
3 - SPRING (3)
4 - STRUT (3)
5 - DETENT BALL (3)
6 - HUB
DRMANUAL TRANSMISSION - NV3500 21 - 17
MANUAL TRANSMISSION - NV3500 (Continued)
(8) Install front thrust washer on shaft and slide
washer up against gear and over lock ball (Fig. 80).
(9) Install wave washer, flat washer and remain-
ing snap ring on idler shaft (Fig. 80). Verify snap
ring is seated.
SHIFT SHAFT AND DETENT PLUNGER BUSHINGS/
BEARINGS
(1) Inspect shift shaft bushing and bearing for
damage.
(2) If necessary, the shift shaft bushing can be
replaced as follows:
(a) Locate a bolt that will thread into the bush-
ing without great effort.
(b) Thread the bolt into the bushing, allowing
the bolt to make its own threads in the bushing.
(c) Attach a slide hammer or suitable puller to
the bolt and remove bushing.(d) Use the short end of Installer 8119 to install
the new bushing.
(e) Bushing is correctly installed if flush with
the transmission case.
(3) If necessary, the shift shaft bearing can be
replaced as follows:
(a) Locate a bolt that will thread into the bear-
ing without great effort.
(b) Thread the bolt into the bearing as much as
possible.
(c) Attach a slide hammer or suitable puller to
the bolt and remove the bearing.
(d) Use the short end of Installer 8119 to install
the new bearing.
(e) Bearing is correctly installed if flush with the
transmission case.
(4) Inspect detent plunger bushings for damage.
NOTE: The detent plunger bushings are installed to
a specific depth. The space between the two bush-
ings when correctly installed contain an oil feed
hole. Do not attempt to install the bushings with
anything other than the specified tool or this oil
hole may become restricted.
(5) If necessary, the detent plunger bushings can
be replaced as follows:
(a) Using the long end of Installer 8119, drive
the detent bushings through the outer case and
into the shift shaft bore.
(b) Remove the bushings from the shift shaft
bore.
(c) Install a new detent plunger bushing on the
long end of Installer 8118.
(d) Start bushing in the detent plunger bore in
the case.
(e) Drive bushing into the bore until the tool
contacts the transmission case.
(f) Install a new detent plunger bushing on the
short end of Installer 8118.
(g) Start the bushing in the detent plunger bore
in the case.
(h) Drive bushing into the bore until the tool
contacts the transmission case.
Fig. 80 IDLER GEAR & SHAFT ASSEMBLY
1 - REAR OF SHAFT
2 - GEAR
3 - THRUST WASHER AND BALL
4 - WAVE WASHER
5 - FLAT WASHER
6 - FRONT OF SHAFT
7 - SNAP RING
8 - SNAP RING
21 - 26 MANUAL TRANSMISSION - NV3500DR
MANUAL TRANSMISSION - NV3500 (Continued)
MANUAL TRANSMISSION - NV4500
TABLE OF CONTENTS
page page
MANUAL TRANSMISSION - NV4500
DESCRIPTION.........................43
OPERATION...........................43
DIAGNOSIS AND TESTING................44
REMOVAL.............................44
DISASSEMBLY.........................46
CLEANING............................62
INSPECTION..........................62
ASSEMBLY............................63
INSTALLATION.........................80
SPECIFICATIONS.......................81
SPECIAL TOOLS.......................81ADAPTER HOUSING SEAL
REMOVAL.............................85
INSTALLATION.........................85
EXTENSION HOUSING SEAL
REMOVAL.............................85
INSTALLATION.........................85
SHIFT MECHANISM
REMOVAL.............................86
INSTALLATION.........................87
SHIFT COVER
REMOVAL.............................87
INSTALLATION.........................87
MANUAL TRANSMISSION -
NV4500
DESCRIPTION
The NV4500 is a five speed constant mesh manual
transmission. All gear ranges including reverse are
synchronized. Fifth gear is an overdrive range. The
transmission has a cast iron gear case and aluminum
shift cover.
Two versions are used, a standard duty for 5.7L
applications and a heavy duty for V10 and Cummins
diesel applications. Main difference is a larger diam-
eter input shaft, for the heavy duty model.
Tapered roller bearings support the drive gear,
mainshaft and countershaft in the gear case. Roller
bearings in the drive gear support the forward end of
the mainshaft. The mainshaft gears are all supported
on caged type roller bearings. Drive gear thrust reac-
tion is controlled by a needle type thrust bearing.
The bearing is located at the forward end of the
mainshaft.
The transmission is a top loader style. The shift
lever is located in a shifter tower which is bolted to
the shift cover and operates the shift forks and rails
directly. The shift forks and rails are all located
within the aluminum cover which is bolted to the top
of the gear case.
IDENTIFICATION
The transmission identification tag is attached to
the driver side PTO cover (Fig. 1).
The tag provides the transmission model number,
build date and part number. Be sure to reinstall the
I.D. tag if removed during service. The information
on the tag is essential to correct parts ordering.
OPERATION
The manual transmission receives power through
the clutch assembly from the engine. The clutch disc
is splined to the transmission input shaft and is
turned at engine speed at all times that the clutch is
engaged. The input shaft is connected to the trans-
mission countershaft through the mesh of fourth
speed gear on the input shaft and the fourth counter-
shaft gear. At this point all the transmission gears
are spinning.
Fig. 1 IDENTIFICATION TAG LOCATION
1 - PTO COVER
2 - I.D. TAG
DRMANUAL TRANSMISSION - NV4500 21 - 43
The driver selects a particular gear by moving the
shift lever to the desired gear position. This move-
ment moves the internal transmission shift compo-
nents to begin the shift sequence. As the shift lever
moves the selected shift rail, the shift fork attached
to that rail begins to move. The fork is positioned in
a groove in the outer circumference of the synchro-
nizer sleeve. As the shift fork moves the synchronizer
sleeve, the synchronizer begins to speed-up or slow
down the selected gear (depending on whether the
driver is up-shifting or down-shifting). The synchro-
nizer 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 fric-
tion 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 syn-
chronizer sleeve become aligned with the teeth on
the blocker ring and the friction cone and eventually
will slide over the teeth, locking the gear to the
mainshaft, 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 so
before 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 isnoise, 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.
(2) Remove shift boot screws from floorpan and
slide boot upward on the shift lever.
(3) Remove shift lever extension from shift tower
and lever assembly.
(4) Remove shift tower bolts (Fig. 2).
Fig. 2 SHIFT TOWER
1 - SHIFT TOWER
2 - SHIFTER
3 - BOLTS
21 - 44 MANUAL TRANSMISSION - NV4500DR
MANUAL TRANSMISSION - NV4500 (Continued)
(5) Remove shift tower and isolator plate from
transmission shift cover.
(6) Raise and support vehicle.
(7) Remove skid plate, if equipped.
(8) Mark propeller shaft and axle yokes for instal-
lation reference and remove shaft/shafts.
(9) Remove exhaust system Y-pipe.
(10) Disconnect speed sensor and backup light
switch connectors.
(11) Support engine with safety stand and a wood
block.
(12) If transmission is to be disassembled, remove
drain bolt at bottom of PTO cover and drain lubri-
cant (Fig. 3).
TWO WHEEL DRIVE
(1) Remove bolts attaching transmission to rear
crossmember mount.
(2) Support and secure transmission with safety
chains to a transmission jack.
(3) Remove rear crossmember bolts and pry out
crossmenber.
(4) Remove clutch slave cylinder bolts and move
cylinder aside for clearance.
NOTE: The hydraulic linkage has a quick connect at
the slave cylinder. This fitting should not be discon-
nected.
(5) Remove transmission harness wires from clips
on transmission shift cover.
(6) Remove transmission to clutch housing bolts.
(7) Slide transmission and jack rearward until
input shaft clears clutch housing.
(8) Lower transmission jack and remove transmis-
sion from under vehicle.
FOUR WHEEL DRIVE
(1) Disconnect transfer case shift linkage at trans-
fer case range lever. Then remove transfer case shift
mechanism from transmission (Fig. 4).
(2) Support and secure transfer case to transmis-
sion jack with safety chains.
(3) Remove transfer case mounting nuts.
(4) Move transfer case rearward until input gear
clears transmission mainshaft.
(5) Lower transfer case assembly and move it from
under vehicle.
(6) Support and secure transmission with safety
chains to a transmission jack.
(7) Remove transmission harness from retaining
clips on transmission shift cover.
(8) Remove bolts/nuts attaching transmission
mount to rear crossmember.
(9) Remove rear crossmember bolts and pry out
crossmenber.
(10) Remove clutch slave cylinder splash shield, if
equipped.
(11) Remove clutch slave cylinder bolts and move
cylinder aside for clearance.
NOTE: The hydraulic linkage has a quick connect at
the slave cylinder. This fitting should not be discon-
nected.
(12) Remove transmission to clutch housing bolts.
(13) Slide transmission and jack rearward until
input shaft clears clutch housing.
(14) Lower transmission jack and remove trans-
mission from under vehicle.
Fig. 3 FILL AND DRAIN PLUGS
1 - PTO COVER
2 - DRAIN BOLT
3 - FILL PLUG
Fig. 4 TRANSFER CASE SHIFTER-TYPICAL
1 - TRANSMISSION
2 - TRANSFER CASE SHIFT MECHANISM
DRMANUAL TRANSMISSION - NV4500 21 - 45
MANUAL TRANSMISSION - NV4500 (Continued)
(12) Position second puller jaw on gear and in
notch of puller flange (Fig. 17). Slide Collar 6444-8
over puller jaws to hold them in place.
(13) Install Puller and Bolt 6444 on puller rods
and secure puller to rods with retaining nuts (Fig.
18). Tighten puller bolt to remove gear from shaft
splines.(14) Remove mainshaft rear bearing plate bolts
and remove fifth gear plate end play shims and bear-
ing cup (Fig. 19).
FRONT RETAINER
(1) Remove and discard front bearing retainer
bolts (Fig. 20).
CAUTION: Do not reuse retainer bolts.
(2) Lightly tap retainer back and forth with plastic
mallet to work it out of gear case.
NOTE: Retainer flange extends into transmission
case and is a snug fit.
Fig. 17 PULLER COLLAR
1-JAWS
2 - COLLAR
Fig. 18 PULLER ASSEMBLY
1 - COLLAR
2-JAWS
3 - BOLT
4 - WRENCH
5 - MAINSHAFT
6 - PULLER FLANGE
Fig. 19 FIFTH GEAR BEARING PLATE, SHIMS AND
BEARING CUP
1 - MAINSHAFT REAR BEARING CUP
2 - BEARING SHIMS
3 - BEARING PLATE
4 - FIFTH GEAR
Fig. 20 FRONT BEARING RETAINER
1 - DRIVE GEAR
2 - FRONT BEARING RETAINER
DRMANUAL TRANSMISSION - NV4500 21 - 49
MANUAL TRANSMISSION - NV4500 (Continued)
DRIVE GEAR
(1) Remove drive gear (Fig. 25).
(2) Remove pilot bearing from drive gear (Fig. 26).(3) Remove tapered bearing from drive gear with
Puller Flange 6444-1 and Puller Rods 6444-6 (Fig.
27).
(4) Position first Jaw 6447 on bearing. Slide
assembled puller flange and rod tools onto input
shaft. Then seat flange in notch of puller jaw.
(5) Position second Jaw 6447 on gear and in notch
of puller flange. Slide Collar 6444-8 over puller jaws
to hold them in place.
(6) Install Puller 6444 on puller rods then install
retaining nuts. Tighten puller bolt to remove bearing
cone from drive gear.
Fig. 25 DRIVE GEAR
1 - MAINSHAFT
2 - DRIVE GEAR
Fig. 26 PILOT BEARING
1 - DRIVE GEAR
2 - MAINSHAFT PILOT BEARING
Fig. 27 FRONT BEARING PULLER
1 - PULLER
2 - RODS
3-JAWS
4 - COLLAR
5 - FLANGE
6 - DRIVE GEAR
DRMANUAL TRANSMISSION - NV4500 21 - 51
MANUAL TRANSMISSION - NV4500 (Continued)