ARB RD40 - Manual (Page 15)

3 Installing the Air Locker
13
While supporting the pinion gear by holding the drive shaft, rotate
the differential in both directions while observing the maximum
variation in depth from the indicator (i.e., the highest value minus
the lowest value).
Set the backlash to a value less than 0.5mm [0.02”] by rotating the
adjuster nuts.
NOTE : This backlash value is for the tube position only and
will not be used for final assembly.
3.6 Marking the Bearing Cap for Tube Clearance
With the Air Locker in place and less than 0.5mm of backlash, an
accurate measurement for the seal housing tube clearance can be
made.
NOTE : Take time and double check when taking your
measurements, as bearing caps are custom fitted to
the axle housing and cannot be replaced.
With the seal housing tube pointing straight out, measure the
distance from a fixed position inside the differential housing to the
center of the seal housing tube. (Fig.7.)
Figure 7.
Record your findings and recheck for accuracy.
Remove the bearing cap from the ring gear side of the differential.
Remove the Air Locker from the differential housing.