Lull 1044C-54 Series II Service Manual - Manual (Page 313)

Frame Tilt and Oscillation
31200079 7-31
Oscillation Control Block
Description
Fig. 7-19: Oscillation Control Block
(Ref. Fig. 7-19) The oscillation control block assembly controls the function
of the rear oscillation lock cylinder.
When the oscillation lock system is in UNLOCK mode, the control block
allows hydraulic fluid to freely pass into and out of the cylinder.
When the oscillation lock system is in LOCK mode, the control block traps
hydraulic fluid in both the rod-end and base-end of the cylinder. This
hydraulic lock in the cylinder prevents the frame from rotating on the rear
axle.
MV0750
Rear Oscillation
Lock Control Block