TM 10-3930-669-20 9.  LIFT CYLINDER(S) WILL NOT HOLD LOAD (DOWNDRIFT) (CONT). KNOWN INFO TEST OPTIONS Lift cylinder hose(s) OK. Lift cylinder(s) OK. Lift control cable OK. Visual inspection. POSSIBLE PROBLEMS REASON FOR QUESTION Stack valve faulty. Hydraulic reservoir return hoses leaking or damaged. If     stack     valve     is     faulty,     lift cylinder will not hold load. KNOWN INFO TEST OPTIONS Lift cylinder hose(s) OK. Lift cylinder(s) OK. Lift control cable OK. Stack valve OK. Visual inspection. POSSIBLE PROBLEMS REASON FOR QUESTION Hydraulic reservoir return hose leaking or damaged. If    reservoir    return    hoses    are faulty,  lift  cylinders  will  not  hold load. ¬ ¬ 2-478