Tractor Repair: case international 885 4wd, case international, pressure regulator

Question
Hi, I am having a problem with my pto in a case 885. It wont drive under load. the clutch has been replace and the problem persists. The mmachine has a front loader which works perfectly. Have you any ideas what might be the problem and how to fix it,
Thanks

Answer
  The pressure to the pto clutch should be checked with a gauge, and it should be about 300 psi.  If the pressure is low, it could cause the pto to slip.  There is a tee fitting under the left rear axle where the pressure can be checked.  Low pressure could be caused by an internal oil leak, the pto lever linkage not properly adjusted, or a sticking pressure regulator spool in the multiple control valve.