A hydraulic assembly for controlling position of portions of a lift arm assembly, the lift arm assembly including a main lift arm portion, an extendable lift arm portion configured to be extended relative to the main lift arm portion, and an implement interface for supporting an implement, the hydraulic assembly comprising: a leveling cylinder (710; 810) configured to adjust an attitude of the implement relative to the extendable lift arm portion, causing one of a tensile load and a compression load on the leveling cylinder depending a load introduced by an implement attached to the implement interface; an extension cylinder (712; 812) configured to move the extendable lift arm portion relative to the main lift arm portion; a main control valve (704; 804) configured to control commanded movement of the extension and leveling cylinders by selectively directing flow along a first hydraulic flow path (706; 806) to rod ends of the extension and leveling cylinders or along a second hydraulic flow path (708; 808) to base ends of the leveling and extension cylinders; a flow combiner/divider (718; 818) along one of the first or second hydraulic flow paths, the flow combiner/divider configured to divide hydraulic flow to, respectively, one of (i) the rod ends of the extension and leveling cylinders during retraction of the extension and leveling cylinders or (ii) the base ends of the extension and leveling cylinders during extension of the extension and leveling cylinders, and to combine hydraulic flow from, respectively, one of (i) the rod ends of the extension and leveling cylinders during extension of the extension and leveling cylinders or (ii) the base ends of the extension and leveling cylinders during retraction of the extension and leveling cylinders, for synchronized operation of the leveling and extension cylinders when the extension cylinder is under tension; and a lock valve (728; 828) arranged along one of the first hydraulic flow path and the second hydraulic flow path; the lock valve being configured to be moved to a first configuration during commanded movement of the extension and leveling cylinders and to a second configuration when there is no commanded movement of the extension and leveling cylinders; the first configuration of the lock valve permitting hydraulic flow between the rod ends of the extension and leveling cylinders; and the second configuration of the lock valve blocking hydraulic flow between the rod ends of the extension and leveling cylinders. a leveling cylinder (710; 810) configured to adjust an attitude of the implement relative to the extendable lift arm portion, causing one of a tensile load and a compression load on the leveling cylinder depending a load introduced by an implement attached to the implement interface; an extension cylinder (712; 812) configured to move the extendable lift arm portion relative to the main lift arm portion; a main control valve (704; 804) configured to control commanded movement of the extension and leveling cylinders by selectively directing flow along a first hydraulic flow path (706; 806) to rod ends of the extension and leveling cylinders or along a second hydraulic flow path (708; 808) to base ends of the leveling and extension cylinders; a flow combiner/divider (718; 818) along one of the first or second hydraulic flow paths, the flow combiner/divider configured to divide hydraulic flow to, respectively, one of (i) the rod ends of the extension and leveling cylinders during retraction of the extension and leveling cylinders or (ii) the base ends of the extension and leveling cylinders during extension of the extension and leveling cylinders, and to combine hydraulic flow from, respectively, one of (i) the rod ends of the extension and leveling cylinders during extension of the extension and leveling cylinders or (ii) the base ends of the extension and leveling cylinders during retraction of the extension and leveling cylinders, for synchronized operation of the leveling and extension cylinders when the extension cylinder is under tension; and a lock valve (728; 828) arranged along one of the first hydraulic flow path and the second hydraulic flow path; the lock valve being configured to be moved to a first configuration during commanded movement of the extension and leveling cylinders and to a second configuration when there is no commanded movement of the extension and leveling cylinders; the first configuration of the lock valve permitting hydraulic flow between the rod ends of the extension and leveling cylinders; and the second configuration of the lock valve blocking hydraulic flow between the rod ends of the extension and leveling cylinders.