ARB RD121 - Manual (Page 8)

2 Removing the Existing Differential
6
2.4 Checking the Current Backlash Amount
IMPORTANT:
This step is a precautionary measure recommended by ARB due
to the fact that some aftermarket ring and pinion sets have been
manufactured to run with different backlash settings than those
specified by your vehicle manufacturer. Although ARB must
recommend you set backlash according to your service manual
guidelines, we also advise that you compare the backlash
measurements taken here to the recommended backlash settings
in your vehicle service manual. Measurements found to be
outside of your service manual recommendations may indicate
the need to deviate from those settings in order to achieve quiet
running with a good contact mark.
Refer to your vehicle service manual or your local authorized
ARB installer for more information.
c Set a long series lever type dial indicator on one of the ring gear
teeth. Access to the ring gear teeth is gained through the oil filler
hole. (Refer to Figure 1.)
Figure 1.
c Insert a large flat screwdriver or pry-bar through one of the axle
stub holes so that it wedges between the cross shaft and the carrier
body so that the differential center can be rotated by the cross
shaft, and not by the spline of one of the differential gears.
c While supporting the pinion gear by holding the drive shaft flange,
rotate the differential in both directions (with the screwdriver or pry-
bar) while observing the maximum variation in depth from the
indicator (i.e., the highest value minus the lowest value). This value
is referred to as the ring and pinion backlash.
c Rotate the differential center 90
°
and measure again for accuracy.
c Record the average of all measurements.