TM  10-3930-638-24&P 3-29.   HYDRAULIC   LIFT   SYSTEM   TROUBLESHOOTING   (cont) MALFUNCTION TEST  OR  INSPECTION CORRECTIVE ACTION 2.  LOAD  DRIFTS  DOWN NOTE After completion of each check, lower forks until resting on ground. Then, turn engine off. With  engine  off,  operate  control  levers  several  times  to relieve  hydraulic  pressure.  Disconnect  hose  assembly connected between control valve and lift cylinder assembly  at  control  valve  (refer  to  illustration). NOTE Increase engine speed as necessary to prevent engine stall. Connect a 3000 PSI pressure gage between elbow on con trol valve and hose assembly. Start  engine  and  place  LIFT  control  lever  in  RAISE position until mast assembly is at full height; continue to hold lever in RAISE position until pressure gage indicates 2500-2550 PSI with engine at full throttle. With LIFT control lever in neutral position, observe pressure gage and mast assembly. a.  If  mast  assembly  drifts  down  and  pressure  gage  indication  does  not  decrease,  remove  and  repair lift cylinder assembly (para 3-30e). b. If pressure gage indication decreases, replace or repair control valve (para 3-30a). 3.  UNABLE  TO  SIDESHIFT  LOAD  (ALL  OTHER  FUNCTIONS  NORMAL) NOTE After completion of each check, turn engine off. Step  1. Check sideshift cylinder assembly for hydraulic oil leakage. a. If hydraulic oil leakage is observed, remove and repair sideshift cylinder assembly (para 3-30c). b. If hydraulic oil leakage is not observed, proceed to step 2. Step 2. Check hose assemblies between side shift cylinder assembly and control valve for hydraulic oil leakage. a. If hydraulic oil leakage is observed at hose assemblies, replace leaking hose assembly (para 2-56 f). b. If hydraulic oil leakage is not observed at hose assemblies, proceed to step 3. 3-197