Chrysler DODGE D150 1993 Service Manual page 1343

21 - 342 NP205 TRANSFER CASE
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NP205 T R A N S F E R CASE
INDEX
page
General Information 3 4 2
Recommended Lubricants 3 4 2
Service Diagnosis 3 4 2
Shift Linkage Adjustment 344
Speedometer Service 3 4 5
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 a t ambient temperatures
above this point.
page
Transfer C a s e Assembly 3 4 8
Transfer Case Disassembly . . . . . . . . . . 3 4 5
Transfer Case Identification 3 4 2
Transfer C a s e Installation 3 4 5
Transfer C a s e Removal 3 4 5
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 t h e
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 a t rec­
ommended intervals. Lubrication frequency for the
linkage is described in Lubrication And Maintenance
Group O.
TRANSFER CASE IDENTIFICATION
The NP205 identification t a g is attached to t h e
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 a t t h e shaft seals, case
vent, or gasket joints. Most leaks will be evident by
the presence of lubricant around t h e leakage point.
However, be sure the leakage is actually from a
transfer case component.