Yamaha YFM660FS Grizzly 4x4 Supplementary Service Manual page 95

GEN
FEATURES
INFO
In addition, the 4WD (Diff-Lock) mode can be engaged only when the ATV is stopped. Even if an
attempt is made to select this mode when the ATV is traveling, it will only result in a standby condi-
tion (i.e., when the differential lock select switch and the differential gear are not matched).
(1) When the ATV is traveling
Even if the 4WD (Diff-Lock) mode is selected, the gear motor will stand by, instead of operating.
Therefore, the ATV can be driven in the normal 4WD mode. When this occurs, the differential gear
lock indicator light " " in the speedometer unit will flash to alert the driver that the control is on
DIFF.
LOCK
standby. When the ATV is stopped, the control transfers to the condition described in (2).
(2) When the ATV is stopped
The gear motor operates to connect the drive clutch to the differential case, thus resulting in the
differential lock condition. When this occurs, the differential gear lock indicator light " " in the
DIFF.
LOCK
speedometer unit changes to a constant illumination.
* Until the drive clutch and the differential case mesh together (i.e., the splines are unmeshed) the
engine misfires to control the engine speed. During this time, the differential gear lock indicator light
in the speedometer unit continues to flash.
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