Komatsu GD555-5 Operation & Maintenance Manual page 105

EXPLANATION OF COMPONENTS
LEFT BLADE LIFT CYLINDER CONTROL LEVER
This lever (1) operates the left blade lift cylinder.
(A) LOWER: The left side of the blade goes down.
(B) HOLD: The blade stops and is held in the same position.
(C) RAISE: The left side of the blade goes up.
(D) FLOAT: The blade moves freely according to the external
force.
REMARK
Even after releasing the lever in D (FLOAT) position, it does not
return to B (HOLD) position. Return it manually.
D (FLOAT) position is effective for removal of fresh snow.
NOTICE
Before starting the engine, be sure to return the lever to B (HOLD) position.
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OPERATION