TM 10-3930-671-24 5. Check hydraulic system relief pressure setting at full  throttle.    Accelerate  the   engine   to   no-load governed  speed  (full  throttle),  and  hold  at  this speed while obtaining the pressure readings. 6. Move the tilt control lever to full back (or forward) tilt    relief    position.        Hold    tilt    control    in    relief position  until  pressure  reading  is  obtained,  and then release. NOTE Do not operate system over relief any longer    than    required    to    read    the pressure gauge. Hydraulic System Relief Pressure Specifications GPX 25E 2600-2700 psi Reference Section 2.  1, Service Specifications. Relief Pressure Adjustment NOTE If   adjustment   is   necessary,   do   not exceed    the    relief    pressure    setting specified for the truck model capacity rating.      Changing   the   pressure   will not  increase  lifting  capacity  or  lifting speed. 1. Remove  the  valve  cover  from  the  seat  support plate  for  access  to  the  relief  valve  adjustment screws on the main valve. 2. The   main   hydraulic   system   relief   (1)   and   aux relief (2) valve adjustment screws are located on the upper front side of the main valve. To  adjust,  loosen  the  lock  nut,  reset  and  tighten  lock nut.  Turn adjustment screw clockwise (CW) to increase pressure.      Turn   counterclockwise   (CCW)   to   decrease pressure. 3. If   pressure   relief   valve   needs   to   be   adjusted, loosen the lock nut, hold the control lever in relief position, and turn the relief pressure adjustment screw   until   pressure   gauge   reads   the   correct relief pressure setting.  Tighten the lock nut. 4. IMPORTANT    -    Recheck    the    relief    pressure setting.  With engine running at full throttle, move the  control  lever  to  relief  position  and  read  the pressure   gauge.      This   is   to   verify   that   relief pressure  setting  has  not  been  changed  during the tightening of the locknut. 5. If   pressure   setting   is   not   correct,   repeat   the adjustment procedure. 6. When relief pressure setting is correct, disconnect the pressure gauge.  Put the cap on the   quick   disconnect   fitting.      Install   the   cover enclosing main valve. 7. Close the engine compartment, remove blocking, and lower drive wheels to the floor. This completes the procedure for checking and adjusting main hydraulic relief pressure. F-456