Gason 7390, Operator'S Manual

Page: 25 / 110

Operation - Ground Drive
Page 21
07/18
Changing Gearbox Ratio
The feed chain spreader is equipped with
a ground driven 3-speed gearbox. The gearbox
has been designed to offer a large variation in
feed chain speeds to cope with the low and high
application rates.
Fig.32 Ground driven Gearbox.
To change between ratios you will need to
remove the clip from the inside face of the top
shaft (opposite the jockey wheel) on the
gearbox.
Fig.33 Selector pin and clip.
Once removed, the selector pin can be
moved in to select low ratio, centralised to select
high ratio or fully withdrawn to drive medium
ratio. It will be necessary to either rock the jockey
wheel backwards and forwards or to slowly turn
the jockey wheel to allow the internal drive key
to slide from one gear to the next.
Fig.34 .Selector pin central.
Once the correct ratio has been chosen
replace the retaining clip to lock the selector pin
into position.
Note: Always use the lowest gear
possible at the highest door setting to
minimise the loading on the gearbox.
Caution:
The rear door should never be operated
in the closed position with fertiliser that can
pack. On some fertilisers it should not be
operated with less than 40mm of gap as
packing will occur and the chain will jam.
IMPORTANT: Grease gearbox before
using. Ensure that the gear selector pin
has been fully pushed in before greasing
the nipple at the end of the pin.
Refer to the daily maintenance section on page 35
for further information.