ARB RD109 - Manual (Page 12)

3 Installing the Air Locker
10
3.1 Insuring Adequate Oil Drainage
IMPORTANT:
Some Salisbury axles were manufactured with poor oil drainage
between the axle tubes and the differential housing. This can
often result in one of the axle tubes filling up with differential oil
while running. In most cases this will result in a blocked air vent
which will cause the differential housing to pressurize and expel
oil from the axle seals at the wheels or force oil into the air
system of the Air Locker, eventually expelling oil at the solenoid
valve. This is a design flaw which was corrected by most
automakers in the later releases of their axle assemblies. If no
lower drainage point is present in the differential housing then it
is critical that you modify the housing to include one.
Inspect the differential housing for the presence of adequate
drainage in both axle tubes (refer to Fig.4.).
Figure 4.
If no drainage slot is present at the left-hand side (refer to Fig.4.) of
the housing at all, then a slot will have to be created as clearance
for the seal housing tube (Refer to Section 3.8 Reinstalling the
Bearing Caps).
If drainage exists but is inadequate then a slot or hole should be cut
into the housing on the lower side of the tube(s) to allow oil out of
the axle tube area.