1993 DODGE TRUCK Service Repair Manual

21 - 336
OVERDRIVE
UNIT
OVERHAUL—42RH/46RH

CLUTCH
DISCS
(6) A
42RH

PRESSURE
PLATE
REACTION

PLATE

CLUTCH
PLATES
(5)
CLUTCH
DISCS
(8)
46RH

PRESSURE
PLATE

REACTION
PLATE

COUNTERBORE

REACTION
CLUTCH

PLATE
PLATES
(7)
Fig. 48 Direct Clutch Pack Components (c) Check direct clutch pack. 42RH requires 6
discs and 5 steel plates. 46RH requires 8 discs and 7 steel plates (Fig. 48).
(d) Last clutch pack item installed is clutch pres­
sure plate. Be sure plate is installed with shoulder
side of plate facing upward (Fig. 50). (23) Install clutch hub and clutch pack on direct
clutch spring (Fig. 51).
(24) Mount geartrain assembly in shop press (Fig.
52)

WARNING:
THE
NEXT
STEP
IN
GEARTRAIN
AS­
SEMBLY
INVOLVES COMPRESSING
THE
DIRECT CLUTCH
HUB AND
SPRING.
IT IS
EXTREMELY
IM­
PORTANT
THAT
PROPER EQUIPMENT
BE
USED
TO COMPRESS
THE
SPRING AS SPRING FORCE
IS
APPROXIMATELY 800 POUNDS. USE SPRING COM­
PRESSOR
TOOL
C-6227-1
AND A
HYDRAULIC-
TYPE SHOP
PRESS
WITH
A
MINIMUM
RAM

TRAVEL
OF
5-6 INCHES.
THE
PRESS
MUST ALSO HAVE
A BED
THAT
CAN BE
ADJUSTED
UP OR

DOWN
AS
REQUIRED. RELEASE CLUTCH SPRING
TENSION SLOWLY
AND
COMPLETELY
TO
AVOID
PERSONAL
INJURY.
J922M41

(25) Position Compressor Tool 6227-2 on clutch
hub (Fig. 52). (26) Position Tool MB990891 or similar size tool on
top of compressor tool (Fig. 52). Similar size tool
DIRECT

CLUTCH

REACTION
PLATE

(FLUSH
WITH

END OF
HUB)

CLUTCH
HUB
J9121-329

Fig.
49
Correct
Position
Of
Direct
Clutch
Reaction
Plate

OVERDRIVE
UNIT
OVERHAUL—42RH/4IRH
21 - 337

DIRECT
CLUTCH
PRESSURE PLATE
BE
SURE
SHOULDER

SIDE
OF

PLATE
FACES
UPWARD
CLUTCH
PACK
J9121-330

Fig.
50 Correct Position Of Direct
Clutch
Pressure
Plate
DIRECT
CLUTCH PACK
CLUTCH
HUB
J9121-331

should have minimum outside diameter of 3-1/2 inch,
minimum wall thickness of 1/4 inch and be approxi­
mately 4 inches long.
(27) Slide direct clutch pack upwards on hub (Fig.

52).
Slide pack upward and set it partially on edge of
hub and compressor tool as shown in Figure 52.
SPECIAL
TOOL

MB990891
SPECIAL TOOL 6227-2
CLUTCH
HUB
SPECIAL
TOOL 6227-1
DIRECT
CLUTCH PACK
CLUTCH
DRUM

J9221-2

Fig.
52
Mounting
Geartrain
Assembly
In
Shop
Press
(28) Slowly compress clutch hub and spring (Fig.

53).
Compress spring and hub only enough to expose
ring grooves for clutch pack snap ring and clutch hub
retaining ring.
(29) Realign clutch pack on hub and seat clutch
discs and plates in clutch drum (Fig. 53).
SPECIAL
TOOL 6227-2 DIRECT
CLUTCH
PLATES/DISCS

Fig.
51 Installing
Assembled
Direct
Clutch
Pack
And
CLUTCH
Hub
DRUM J9221-3

Fig.
53 Seating
Clutch
Pack
In
Drum

21
- 338
OVERDRIVE
UNIT
OVERHAUL—42RH/46RH

• (30) Install direct clutch pack snap ring
(Fig. 54).

Be very sure snap ring
Is
fully seated
In
clutch drum ring groove.
(31) Install clutch
hub
retaining ring
(Fig. 55). Be

very sure retaining ring
Is
fully seated
in sun

gear ring groove.
(32) Slowly release press
ram,
remove compressor
tools
and
remove geartrain assembly.

Fig.
54
Installing Direct
Clutch
Pack Snap Ring
J9221-5

Fig.
55
Installing
Clutch
Hub
Retaining
Ring

OVERDRIVE
UNIT ASSEMBLY AND ADJUSTMENT
(1) Install front bearing
and
snap ring
on
output
shaft
(Fig. 56). Be
sure locating ring groove
in

bearing
is
toward rear
of
shaft. (2) Install governor drive
key in
output shaft
(Fig.
56).

(3) Install
new
seal rings
on
governor drive.
Be

sure ring ends
are
securely interlocked before pro­
ceeding
(Fig. 57).
(4) Assemble governor drive
and
body.
Be
sure fil­
ter
is
properly seated
and
positioned
in
governor
body before tightening attaching bolts. (5) Assemble governor inner
and
outer weights
and spring. Then install weight assembly
in
governor
Fig.
56
Front Bearing
And
Drive
Key
Installation

GOVERNOR
BODY

GOVERNOR DRIVE
Fig.
57
Governor
Drive
Seal Rings
Fig.
58
Installing
Governor
Weight
Assembly
body
(Fig. 58). Be
sure
all
retaining snap rings
are

securely seated.

•

OVERDRIVE
UNIT
OVERHAUL—42RH/46RH
21 - 339 (6) Install governor assembly on output shaft (Fig.

59).
Be sure drive key is fully engaged drive slot and
is not displaced during installation.
Fig.
59 Installing
Governor
Assembly

(7) Align shaft holes in governor body and output
shaft and install governor valve and shaft (Fig. 16).
Be very sure that E-clip retainer at each end of
governor valve shaft is securely engaged.
(8) Install governor snap ring (Fig. 17).
(9) Install output shaft rear bearing in case and in­
stall bearing snap ring. Be sure snap ring is fully
seated.
(10) Position park pawl and spring in case and in­
stall park pawl shaft (Fig. 14). Verify that spring end
is hooked to pawl and straight end of spring
(11) Install pawl shaft retaining bolt. Tighten bolt
to 27 Nnn (20 ft. lbs.) torque.
(12) Install park lock reaction plug. Note that
plug has locating pin at rear (Fig.
60).
Be sure
pin is seated in hole in case before installing snap ring.
REACTION

Fig.
60 Reaction
Plug
Locating Pin And
Snap
Ring
(13) Install reaction plug snap ring (Fig. 61). Com­
press snap ring only enough for installation; do
not distort it.
PLIERS
8921-240

Fig.
61 Reaction
Plug
And
Snap
Ring
Installation
(14) Install alignment clip on governor tubes (Fig.

62).
Slide clip up against shoulder on each tube.

GOVERNOR

Fig.
62
Positioning
Governor
Tube
Alignment
Clip (15) Install governor support and pressure tubes in
case (Fig. 63).
Fig.
63 Installing
Governor
Support
And
Pressure

Tubes

21
- 340
OVERDRIVE
UNIT OVERHAUL—42RH/46RH

(16) Install governor support snap ring (Fig. 64).

SNAP
/ ©
^S^^S^
/^SCREWDRIVER RING
7

8921-264

Fig.
64 Installing
Governor
Support
Snap Ring

(17) Install output shaft front bearing locating ring
in case (Fig. 65).
OUTPUT SHAFT
FRONT BEARING LOCATING RING

J9121-339

Fig.
65 Front Bearing Locating
Ring
Installation
(18) Support geartrain on Tool 6227-1 (Fig. 66). Be
sure tool is securely seated in clutch hub. (19) Install overdrive unit case over geartrain (Fig.

66).

(20) Expand front bearing locating ring with snap
ring pliers. Then slide case downward until locating ring locks in bearing groove and release snap ring.
(21) Install locating ring access plate and gasket in
overdrive unit case (Fig. 9).
(22) Install overdrive clutch components as follows: (a) Install reaction ring first. Reaction ring is
flat with notched ends (Fig. 67). (b) Install wave spring on top of reaction ring.
Reaction ring and wave ring both fit in same
ring groove. Use screwdriver to seat each ring se­ curely in groove. (c) Install reaction plate (Fig. 68). (d) Install first clutch disc followed by first
clutch plate.
SPECIAL

TOOL
6227-2
CASE

GEARTRAIN
SPECIAL
TOOL
6227-1

J9221-6

Fig.
66 Installing Overdrive
Case
On
Geartrain
(e) Install remaining clutch discs and plates in
same order.
(f) Verify clutch pack before proceeding:
• gas engine version of 42RH/46RH, requires 4
clutch discs, 3 steel plates, 1 reaction plate and 1
pressure plate.
• diesel engine version of 46RH, requires 5 clutch

discs,
4 steel plates, 1 reaction plate and 1 pressure
plate.
(g) Install clutch pack pressure plate (Fig. 68).
(h) Install clutch pack wire-type retaining ring
(Fig. 67).
WAVE

SPRING

REACTION RING RETAINING RING
(WIRE-TYPE)
J9121-470

Fig.
67 Overdrive
Clutch
Ring
Identification
(23) Place overdrive unit in vertical position.
Mount unit in vise or in workbench with appropriate size mounting hole cut into it. Be sure unit is facing
upward for access to direct clutch hub.

•

NP205
TRANSFER
CASE
21 - 341

REACTION
PLATE

CLUTCH
DISCS
(4)
J9321-227

Fig.
68 Overdrive
Clutch
Pack
(Gas
Engine
Version

Shown)

(24) Determine correct thickness intermediate
shaft spacer as follows: (a) Insert Special Tool 6312 through sun gear, plan­
etary gear and into pilot bushing in output shaft. Be
sure tool bottoms against planetary shoulder.
(b) Position Gauge Tool 6311 across face of over­
drive case (Fig. 69). Then position Dial Caliper C-4962 over gauge tool.
(c) Extend sliding scale of dial caliper downward
through gauge tool slot until scale contacts end of
Alignment Tool 6312. Lock scale in place. Remove
dial caliper tool and note distance measured (Fig. 69). (d) Select proper thickness end play spacer from
spacer chart based on distance measured (Fig. 70). (e) Remove Alignment Tool 6312.
SPECIAL

TOOL
6311

SPECIAL

TOOL
6312

J9221-47
Fig.
69 Shaft End Play Measurement
(25) Determine correct thickness overdrive piston
thrust plate as follows: (a) Position Gauge Tool 6311 across face of over­
drive case. Then position Dial Caliper C-4962 over
gauge tool (Fig. 71).
(b) Measure distance to clutch hub thrust bear­
ing seat at four points 90° apart. Then average
measurements by adding them and dividing by 4.
End
Play

Measurement
(Inches)
Spacer
Thickness
(Inches)

.7336
-
.7505
.158
- .159

.7506
-
.7675
.175
- .176

.7676
-
.7855
.193
- .194

.7856-
.8011
.211
- .212

J9121-341 Fig. 70
Intermediate
Shaft
End
Play
Spacer
Selection

(c) Select and install required thrust plate from in­
formation provided in thrust plate chart (Fig. 72).
(26) Leave Alignment Tool 6227-2 in place. Tool
will keep planetary and clutch hub splines in align­
ment until overdrive unit is ready for installation on
transmission.
(27) Set overdrive unit aside for final assembly of
transmission.

Fig.
71 Overdrive
Piston
Thrust
Plate
Measurement
End
Ploy

Measurement
(Inches)
Spacer
Thickness
(Inches)

1.7500
- 1.7649
.108
- .110

1.7650-
1.7799
.123
- .125

1.7800
- 1.7949
.138
- .140

1.7950
- 1.8099
.153
- .155

1.8100
- 1.8249
.168
- .170

1.8250
- 1.8399
.183
- .185

1.8400
- 1.8549
.198
- .200

1.8550
- 1.8699
.213
- .215

1.8700
- 1.8849
.228
- .230

1.8850
- 1.8999
.243
- .245

J9121-342

Fig.
72 Overdrive
Piston
Thrust
Plate
Selection

21
- 342
NP205 TRANSFER CASE

•
NP205
TRANSFER CASE

INDEX
page
General
Information
342
Recommended Lubricants
342

Service Diagnosis
342

Shift
Linkage
Adjustment
344

Speedometer Service
345

GENERAL
INFORMATION

The NP205 transfer case
is a
heavy duty, part-time
unit with constant mesh, helical gears.
The
gears
are

mounted
in a
one-piece, cast iron gear case. The NP205 provides four operating ranges which

are:
4-wheel drive high, neutral, 2-wheel drive high
and 4-wheel drive
low (Fig. 1).
The transfer case gears rotate
on
shafts supported
by ball
and
roller bearings. Sliding clutch sleeves and shift forks
are
used
to
engage
or
disengage
the

drive gears. The NP205 geartrain provides high
and low
ranges
in 4-wheel drive mode.
The
high range
has a 1:1 ra­

tio
for
normal operation
and a low
range with
a re­
duction ratio
of 1.96:1 for
extra pulling power
in off

road situations. In two-wheel drive range,
the
transfer case front
output shaft drive gear
is
disengaged. Torque
is not

transmitted
to the
front propeller shaft.
Fig.
1
NP205 Transfer
case

RECOMMENDED
LUBRICANTS
Recommended lubricants
for the
NP205 transfer
case include multi-purpose gear lubricants
and
single
weight engine oils. Engine
oil
should
be API
classification SF/CC
or

SF/CD.
Use SAE 30 at
ambient temperatures below
0°
C
(
+
32°
F) and SAE 50 at
ambient temperatures
above this point.
page
Transfer
Case
Assembly
348

Transfer
Case
Disassembly
..........
345

Transfer
Case
Identification
342

Transfer
Case
Installation
345

Transfer
Case
Removal
345

SAE multi-purpose gear lubricants with
an API

grade rating
of GL 5 are
recommended
for
severe
duty operation.
SAE
grades
80,
75W-90,
90,
80W-90, 140
and
80W-140
are all
acceptable.
Use
SAE 80 or
75W-90 when ambient tempera­
tures
are
below
-23° C (-10° F). Use SAE 90, or
80W-90 when ambient temperature
is
above
the

stated range.
SAE
140, or
80W-140
can be
used when severe ser­
vice
is
anticipated,
or
when ambient temperatures are expected
to
exceed +32°
C (90° F).

Transfer Case Shift Linkage Lubrication
The transfer case shift linkage pivot
and
contact
surfaces should
be
lubricated with engine
oil at
rec­
ommended intervals. Lubrication frequency
for the

linkage
is
described
in
Lubrication
And
Maintenance Group
O.

TRANSFER CASE
IDENTIFICATION
The NP205 identification
tag is
attached
to the

PTO cover
on the
driver side
of the
transfer case.
The
tag
contains transfer case manufacturing
and as­
sembly part numbers. Refer
to
this information when
ordering service replacement parts.

SERVICE
DIAGNOSIS
The most frequent causes
of
transfer case malfunc­
tions
are:
• improper operation
• insufficient lubricant
• non-recommended lubricant
• misadjusted shift linkage
• improper assembly after repair. The general problems
and
causes
of
transfer case
malfunctions
are
outlined below.

LOW LUBRICANT LEVEL
A
low
lubricant level
is
usually
the
result
of
loose
components, leakage,
or
improper checking and/or
filling techniques. Lubricant leaks
can
occur
at the
shaft seals, case
vent,
or
gasket joints. Most leaks will
be
evident
by

the presence
of
lubricant around
the
leakage point. However,
be
sure
the
leakage
is
actually from
a

transfer case component.

•

NP205 TRANSFER
CASE
21 - 343 Leakage from other sources (engine, transmission,
etc.) can be blown back onto the transfer case by air
flow under the vehicle. A blocked transfer case vent
can also cause leakage at the shaft seals due to in­
ternal pressure build up.
Overfilling the transfer case can force fluid out the
vent and be mistaken for a leak. Correct fluid level checking methods should prevent overfill problems.

Checking
Fluid Level The correct method of checking transfer case fluid
level requires that the vehicle be level.
If fluid level is checked with the vehicle parked on
the shop floor, be sure the floor area used is level. If a hoist is used, a drive-on, or swivel arm type is pre­
ferred.
Allow the transfer case fluid to settle for a minute
or so before checking. Correct fluid level is to the
bottom edge of the fill plug hole.

HARD SHIFTING
Hard shifting is generally caused by:
• misadjusted or binding linkage
• loose linkage or driveline components
• torque loads caused by 4WD operation on hard
paved surfaces • improper shifting techniques
• lack of lubricant which caused internal wear and
damage.
Loose linkage or driveline components are a result
of improperly tightened, stripped, or missing fasten­

ers.
Remember that loose crossmember and mounting
parts can also generate a hard shift condition.
Torque loads in the transfer case can cause hard
shifting or even prevent shifting. Such loads are gen­
erally a product of extensive operation on hard,
paved surfaces in 4WD range, unequal size tires, or
by mismatched front/rear axle gear ratios.
Linkage adjustment should be performed as de­
scribed in the service section. Improper shift and op­
erating techniques can be corrected by instructing
the driver. Internal component damage will require
overhaul to correct.
Failure to lubricate the shift linkage at recom­
mended intervals will cause the linkage to bind. If
bind is severe enough to cause hard shifting, the linkage will have to be removed in order to correct
the condition. The linkage can be soaked in auto­
matic transmission fluid if necessary. The fluid will
break up accumulated rust and corrosion.

NOISE
Some transfer case operating noise is normal. The
rotating gear train can produce sounds that may be­
come audible at higher speeds and loads. However,
unusual noise is an indicator that internal compo­ nents may be worn or damaged. Low lubricant levels are a frequent cause of noisy
operation. Insufficient lubricant will lead to over­
heating, subsequent damage to bearing and gear sur­
faces and hard shifting.
Transfer case bearing noise is higher in pitch than
gear noise. If the unit is noisy in 4WD range only,
the front shaft bearings are probably at fault. If the unit is noisy in all ranges, an overhaul will be nec­
essary to locate the faulty bearing.
Gear noise is lower in pitch and usually most no­
ticeable when engaged and under load. Gear noise in
4WD drive range only is an indicator that the front shaft gears are damaged. Noise in all ranges could be
the idler or drive gears. An overhaul will be neces­ sary to determine which is at fault.
Frequently, suspected transfer case noise may actu­
ally originate from another driveline component. The
proximity of other driveline components can some­
times make it difficult to pinpoint the noise source.

TRANSFER CASE OPERATIONAL CHECK
The transfer case should not be removed until di­
agnosis indicates the unit has actually malfunc­
tioned. If a transfer case problem is suspected, check and verify operation before attempting repair. A
transfer case operational check may reveal that a
problem is actually related to another driveline com­ ponent.
(1) Raise vehicle on a hoist that will allow all four
wheels to rotate. (2) Check lubricant level. If lubricant level is low,
check for leaks at the bearing and seal retainers,

yokes,
drain/fill plugs, PTO cover and vent. (3) If vehicle is equipped with locking hubs, en­
gage hubs. (4) Start engine, shift transmission into gear and
operate transfer case in all ranges. Observe propeller shaft action, shift efforts and operational sound lev­
els as follows: (a) Only the rear propeller shaft should rotate in
two-wheel drive. Both propeller shafts should both
rotate in four-wheel drive high and low ranges. (b) If the front propeller shaft did not rotate in
either four-wheel drive range, the transfer case shift components may be worn or damaged. Or, if
the front shaft did rotate but the front wheels did
not, check the front axle shift mechanism and the locking hubs (if equipped). (c) If both propeller shafts rotate in four-wheel
drive but the wheels on one axle did not rotate, the
problem is in the axle. (d) If neither propeller shaft rotates in any
range, the problem is in the transmission or trans­ fer case. To determine which component is at fault,
proceed to next step. (5) Determine if fault is with transfer case or
transmission as follows: