MCi Crusader II 1989 Maintenance Manual page 30

Date
1-1-89
Page 2-2
MC-9 MAINTENANCE MANUAL
DRAIN
FILL
Figure 2-2. Drive Axle Housing.
Clean all magnetic drain plugs prior to reinstallation.
1. Fill axle housing to the correct level with specified lubri-
cant with the vehicles on level ground. Use general purpose
gear lubricant SAE 90 above 0°F. (-18°C.J or SAE 140 below
0°F. (-18°C.).
2. Lubricate universal joint.
3. Drive the vehicle. unloaded. for one to two miles at speeds
not to exceed 25 miles per hour to thoroughly circulate the
lubricant throughout the assembly.
For reconditioned axles. follow the same procedures as
above. after overhaul.
OIL CHANGE INTERVALS
Gear oil should be changed every 25.000-30.000 miles
(40.000-48.000 km) on units run over 60,000 miles (96,000 km)
annually.
For units run. less than 60.000 miles. the oil should be
changed twice yearly (spring and fall) regardless of mileage.
The Rockwell axle drive unit employs the gravity feed
(splash) system of distributing lubricant throughout the assem-
bly. As the vehicle is initially driven in service. a short period of
time is required for the lubricant to reach all areas of the drive
units.
MAINTENANCE
Careful adherence to maintenance and lubrication proce-
dures will go a long way toward successful operation.
The most common causes of drive axle carrier failures are
spinout. shock. fatigue and poor lubrication.
Spinout is defined as excessive differential action. On a
single rear axle. main differential spinout occurs when one
wheel remains stationary while the other wheel is spinning. The
relatively high speed differences between the mating parts
generate heat. and the rate of heat generation increases with
the speed differences. When the heat becomes excessive it can
cause galling of the journals of the cross and the mating differ-
ential pinion bores. In extreme cases of spinout, enough heat
may be generated to weld the differential pinion to the cross and
cause a catastrophic failure.
Shock is another common cause of carrier failure. It results
from a rapidly applied load or force that is severe enough to
exceed the strength of the carrier component and cause it to
crack or fail instantly.
There are a number of operating conditions which can result
in a shock failure:
A.
Hitting dry pavement with a spinning wheel.
B. Missing a shift.
C. "Popping" the clutch.
D. Reverse interlock failure.
If the failed part separates into two or more pieces. the
opera~or will usually realize the fact immediately. But if the part
. is only cracked. the operator may not be aware of the damage
until sometime later. Depending on the severity of the crack in
the part. the final failure may not occur until many miles later. the
crack will be a point of origin for a fatigue failure. and can
progress until the part fails. Thus the failure could happen while
the vehicle is being operated under normal conditions.
Figure 2-3. Drive Axle Spinout.
GOOD
ROAD
SURFACE