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)
(2) Remove screws attaching shift boot to floorpan.
Then slide boot upward on the shift lever.
(3) Remove the bolts holding the shift tower to the
isolator plate and transmission gear case.
(4) Remove the shift tower and isolator plate from
the transmission gear case.
(5) Raise and support vehicle.
(6) Remove skid plate, if equipped.
(7) Mark propeller shaft/shafts and axle yokes for
installation reference.
(8) Remove propeller shaft.
(9) Disconnect and remove exhaust system as nec-
essary.
(10) Disconnect wires at backup light switch.
(11) Support engine with adjustable safety stand
and wood block.
(12) If transmission is to be disassembled for
repair, remove drain bolt at bottom of PTO cover and
drain lubricant from transmission (Fig. 3).
(13) Remove clutch slave cylinder splash shield, if
equipped.
(14) Remove clutch slave cylinder bolts and move
cylinder aside for clearance.
(15)
Remove wire harness from clips on transmission.
TWO WHEEL DRIVE
(1) Remove bolts/nuts mounting transmission to
the rear mount.
(2) Support and secure transmission with safety
chains to a transmission jack.
(3) Remove rear crossmember bolts and pry out
crossmember.
(4) Remove transmission clutch housing bolts at
the engine block.
(5) Slide transmission and jack rearward until
input shaft clears clutch disc and pressure plate.
(6) 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.
(2) Support and secure transfer case with safety
chains to a transmission jack.
(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 bolts/nuts attaching transmission
mount to rear crossmember.
(8) Remove rear crossmember bolts and pry out
crossmember.
(9) Remove transmission clutch housing bolts at
the engine block.
(10) Move transmission rearward until input shaft
clears clutch disc.
(11) Lower transmission and remove it from under
vehicle.
DISASSEMBLY
NOTE: Use Fixture 8241 for moving and handling
the transmission. The fixture supports the transmis-
sion at the center of gravity in order to ease mount-
ing the transmission into the build fixture.
(1)
Mount the transmission into Fixture 8230 (Fig. 4).
Fig. 3 NV5600 DRAIN BOLT
1 - PTO COVER
2 - DRAIN BOLT
Fig. 4 TRANSMISSION FIXTURE
1 - FIXTURE
2 - TRANSMISSION
DRMANUAL TRANSMISSION - NV5600 21 - 91
MANUAL TRANSMISSION - NV5600 (Continued)
(6) Remove primary shift rail detent plunger (Fig.
9).
(7) Remove clutch housing bolts (10) (Fig. 10) from
inside the housing.(8) Remove shift rail blocker bolt (Fig. 11) from the
side of the transmission gear case.
EXTENSION/ADAPTER HOUSING
(1) Remove bolts holding the extension/adapter
housing onto the transmission gear case.
(2) Remove extension/adapter housing from the
transmission gear case with Puller 8244 (Fig. 12).
NOTE: It may be necessary to straighten the housing
during removal due to the tendency for the reverse
idler shaft to bind into one side of the housing.
Fig. 9 PRIMARY SHIFT RAIL DETENT PLUNGER
1 - DETENT PLUNGER
Fig. 10 CLUTCH HOUSING BOLTS
1 - BOLTS (10)
Fig. 11 SHIFT RAIL BLOCKER BOLT
1 - BLOCKER BOLT
Fig. 12 TRANSMISSION CASE PULLER
1 - PULLER
2 - EXTENSION/ADAPTER HOUSING
DRMANUAL TRANSMISSION - NV5600 21 - 93
MANUAL TRANSMISSION - NV5600 (Continued)
(8) Remove output shaft ball bearing assembly and
reverse thrust washer from the output shaft (Fig.
21).
(9) Remove reverse gear, reverse gear synchronizer
cone, reverse gear outer blocker ring and reverse
gear bearing (Fig. 22).(10) Remove reverse gear bearing sleeve from the
output shaft (Fig. 23).
NOTE: If necessary heat the sleeve slightly with a
heat gun. Do not use a torch to heat the sleeve or
damage to the output shaft may occur.
(11) Remove roll-pin securing the reverse shift fork
to the reverse shift rail witha6mm(7/32 in.) punch
and hammer.
Fig. 21 OUTPUT SHAFT BEARING AND THRUST
WASHER
1 - OUTPUT SHAFT BALL BEARING
2 - THRUST WASHER
Fig. 22 REVERSE GEAR COMPONENTS
1 - REVERSE GEAR
2 - REVERSE BEARING
3 - BLOCKER RING
4 - FRICTION CONE
Fig. 23 REVERSE BEARING SLEEVE
1 - REVERSE GEAR BEARING SLEEVE
21 - 96 MANUAL TRANSMISSION - NV5600DR
MANUAL TRANSMISSION - NV5600 (Continued)
OUTPUT SHAFT BEARINGS
(1) Remove snap-ring holding the pocket bearing
onto the output shaft.
(2) Remove pocket bearing from the output shaft
with Sleeve 6444-8, Jaws 8234, Puller Rods 6444-4
and the remainder of Puller 6444 (Fig. 33).
(3) Remove snap-ring holding the rear output shaft
bearing onto the output shaft.
(4) Use Collar 6444-8, Jaws 8271 and Puller Rods
6444-3 for 4X2 vehicles or Puller Rods 6444-4 for 4X4
vehicles with the remainder of Puller 6444 to remove
the rear output shaft bearing from the output shaft.
(5) Remove rear output shaft thrust washer from
the output shaft.
INPUT SHAFT
(1) Remove fifth gear blocker ring from the input
shaft (Fig. 34).
(2) Remove fifth gear friction cone from the input
shaft (Fig. 35).
Fig. 33 OUTPUT SHAFT POCKET BEARING
1 - PULLER
2-JAWS
Fig. 34 FIFTH GEAR BLOCKER RING
1 - FIFTH GEAR BLOCKER RING
2 - INPUT SHAFT
Fig. 35 FIFTH GEAR FRICTION CONE
1 - FRICTION CONE
2 - INPUT SHAFT
21 - 100 MANUAL TRANSMISSION - NV5600DR
MANUAL TRANSMISSION - NV5600 (Continued)
(3) Remove first gear blocker rings (2) and cones
from the 1-2 synchro assembly (Fig. 39).
(4) Install the remainder of the output shaft into
Fixture 8227 with press blocks under second gear.
(5) Install shaft and Fixture assembly into a shop
press (Fig. 40).
(6) Press second gear, 1-2 synchro assembly and
first gear bearing sleeve from the output shaft.
(7) Remove second gear bearing from the output
shaft.(8) Reverse output shaft in the Fixture 8227 with
press blocks positioned under the 5-6 synchro assem-
bly.
(9) Press the 5-6 synchro assembly from the out-
put shaft.
Fig. 39 FIRST GEAR BLOCKER RINGS AND
FRICTION CONE
1 - OUTPUT SHAFT
2 - FIRST GEAR BLOCKER RINGS
3 - FIRST GEAR FRICTION CONE
Fig. 40 SECOND GEAR, 1-2 SYNCHRO & FIRST
GEAR BEARING SLEEVE
1 - OUTPUT SHAFT
2 - FIRST GEAR BEARING SLEEVE
3 - SECOND GEAR
4 - FIXTURE
5 - 1-2 SYNCHRO
21 - 102 MANUAL TRANSMISSION - NV5600DR
MANUAL TRANSMISSION - NV5600 (Continued)
(10) Remove sixth gear and the sixth gear bearing
from the output shaft (Fig. 41).
COUNTERSHAFT
(1) Install the countershaft into Fixture 8227 with
press blocks located under the fifth countershaft
gear.
(2) Place the assembly into a shop press.
(3) Use Guide 8235 on end of countershaft and
press the countershaft fifth gear from the counter-
shaft (Fig. 42).
(4) Place countershaft in Fixture 8227 with press
blocks placed under the sixth countershaft gear.
(5) Use Guide 8235 on end of countershaft and
press the countershaft sixth gear from the counter-
shaft (Fig. 43).
Fig. 41 SIXTH GEAR COMPONENTS
1 - SIXTH GEAR FRICTION CONE
2 - SIXTH GEAR
3 - OUTPUT SHAFT
4 - SIXTH GEAR BLOCKER RING
5 - 5-6 SYNCHRO
Fig. 42 FIFTH COUNTERSHAFT GEAR
1 - GUIDE
2 - FIFTH COUNTER SHAFT GEAR
3 - FIXTURE
Fig. 43 SIXTH COUNTERSHAFT GEAR
1 - GUIDE
2 - SIXTH COUNTER SHAFT GEAR
3 - FIXTURE
DRMANUAL TRANSMISSION - NV5600 21 - 103
MANUAL TRANSMISSION - NV5600 (Continued)
(6) Remove countershaft from the press and Fix-
ture 8227.
(7) Remove fourth countershaft gear, friction cone,
blocker ring and bearing from the countershaft (Fig.
44).
(8) Install countershaft into Fixture 8227 with
press blocks located under the third countershaft
gear.
(9) Place assembly into a shop press and press
third countershaft gear, 3-4 synchro and fourth coun-
tershaft gear bearing sleeve from the countershaft
(Fig. 45).
(10) Remove countershaft from the press and Fix-
ture 8227.
(11) Remove third countershaft gear bearing from
the countershaft (Fig. 46).
(12) The 2-3 thrust washer should not normally
need to be removed from the countershaft. If neces-
sary slide 2-3 thrust washer off countershaft.
Fig. 44 FOURTH COUNTERSHAFT GEAR
COMPONENTS
1 - FOURTH GEAR BLOCKER RING
2 - FOURTH GEAR BEARING
3 - COUNTERSHAFT
4 - FOURTH GEAR FRICTION CONE
5 - FOURTH COUNTERSHAFT GEAR
Fig. 45 THIRD COUNTERSHAFT GEAR
COMPONENTS
1 - THIRD COUNTERSHAFT GEAR
2 - FIXTURE
3 - 3-4 SYNCHRO
4 - BEARING SLEEVE
5 - COUNTERSHAFT
Fig. 46 THIRD GEAR BEARING
1 - COUNTERSHAFT
2 - 2-3 THRUST WASHER
3 - THIRD COUNTERSHAFT GEAR BEARING
21 - 104 MANUAL TRANSMISSION - NV5600DR
MANUAL TRANSMISSION - NV5600 (Continued)