Volvo Penta AQUAMATIC 280 Workshop Manual page 43

Repair instructions
19. When the correct backlash has been obtained,
dismantle the double bearing box and the clamp ring.
In order to obtain a clear picture of the contact pat-
tern, the gear teeth are coated with a thin coating of
marking dye. Once again assemble the double bear-
ing box and the clamp ring.
NOTE! The cover must still be installed with an ex-
cess number of shims (1).
20. Rotate the gear in the correct direction of rotation
(clockwise) while at the same time braking the gear
forcefully by wedging a wooden brace against the
gear cone. The marking dye is then pressed away
from the contact surface thus giving a picture of the
width and location of the teeth contact.
40
21. Dismantle the gear set and compare the contact
pattern to that of the picture "A". This picture shows
the desired pattern for the drive side of the forward
and reverse gear. The drive side is the convex side of
the gear. The dye pattern should be nearly oval in
form and be positioned half way up on the gear tooth.
It should be displaced towards the small end of the
tooth (towards the gear cup) but not running off the
end of the tooth.
22. If the dye pattern reflects a contact pattern as
shown in picture "B" the shim thickness underneath
the drive gear (double bearing box) must be reduced.
The drive gear then moves towards the driven gears.
The driven gears must then be shimmed out the
same amount to maintain the correct backlash.