Hewland NMT, Servicing Instructions, Page: 9 / 40

PAGE 9
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CROWNWHEEL & PINION BACKLASH SETTING
Requires special tool No. SK-1913
With the pinion shaft correctly fitted, and the correct diff
bearing shims ascertained, the actual backlash can be
measured by means of a dial test indicator against the
notch in the outside diameter of tool SK-1913. Be sure to
take at least 6 backlash readings, turning the crownwheel
30-45 degrees between each reading (this is to ensure
that any variation due to manufacturing tolerances are
taken account of.
The correct backlash figure should be taken from the
card supplied with the gears. If the measured backlash is
incorrect, rectify it by removing some shims (103) from
behind one diff bearing, and inserting them behind the
other, thus moving the diff across in the maincase. Do
not add or discard any shims at this stage, as to do so
would affect the diff bearing preload.
Once the correct backlash has been achieved, replace the
dummy bearings with bearings (83) and confirm that the
backlash is correct.
Note: Dummy are used so that it is easy to change the shims
during the setting procedures. Before fitting the actual diff
bearings, it is important compare thier width with that of the
dummy bearings and compensate the shims accordingly for any
difference.
FIGURE 4