TM 10-3930-669-20 7.  LIFT CYLINDER(S) DOES NOT OPERATE (CONT). KNOWN INFO TEST OPTIONS Side shift cylinder operates. Lift cylinder hoses OK. Stack valve OK. Secondary flow regulator OK. Visual inspection. POSSIBLE PROBLEMS REASON FOR QUESTION Mast assembly faulty. Lift cylinder faulty. If mast assembly is damaged, lift cylinders will not operate.  If mast assembly is OK, lift cylinder(s) is faulty. KNOWN INFO TEST OPTIONS Side shift cylinder operates. Lift cylinder hoses OK. Stack valve OK. Secondary flow regulator OK. Mast assembly OK. Lift cylinder OK. Verify repair. POSSIBLE PROBLEMS REASON FOR QUESTION If  mast  raises  and  lowers,  fault has been corrected. ¬ ¬ 2-466