Tractor Repair: Transmission and hydraulic probl2390 Case, displacement piston, piston pump

Question
Hydraulic remotes do not work, tractor will not move any more, when first started, tractor goes in reverse when the clutch is released even though power shift is in first (happened at least three times), power steering is does not work, seem to hear pump cavitating at higher engine rpm, pto will run by itself when lever is not pulled, tractor will move unless pto quits turning. Problem started after I backed the tractor up for about 400 feet with the pto running (the lever was not pulled at the time, do not know why the pto was running); notice a small amount of smoke coming from transmission oil fill cap, checked oil level was just below the add mark; added 2.5 gal of oil to fill tractor to proper level. Now, when I check the transmission oil level, it is well above the full mark.

Answer
Hello,

  If the power steering quit working besides the remotes and powershift, then there is no oil coming from the reservoir because the remotes and steering run off two separate pumps.  The remotes, 3 point hitch, and regulated circuits (pto, brakes, diff. lock) get their oil from the variable displacement piston pump.  The steering gets its oil from the gear pump.  But both of these pumps get their oil from the charge pump which draws oil through a suction screen inside the transmission, and through the hydraulic filters.   There are a set of beveled gears inside the transmission that drive the pumps and these gears can fail, so you may want to remove the gear pump from the end of the piston pump and crank the engine over a little just to see if the shaft turns.  The pto turning when it is not turned on is probably because the pto brake is not working, or the pto clutch plates are warped.  Smoke coming from the filler cap could be caused by lots of things.  Brakes dragging, powershift clutches bad, pto clutch bad, powershift left in reverse while doing stationary pto work, etc.  Sounds like a definite internal powershift problem if it goes in reverse when in first.