I recommend a vane pump over the gear pump for several reasons.  First, the vane pump is very efficient, pumping more gallons per engine revolution then the gear pump.  Also the vane pump is much better in cold weather as the vanes do not come out to pump oil until the spinning of the turning shaft forces them out.  By that time the engine has started.  What that means is that the battery and starter didn’t have to start a cold engine and pump oil at the same time.  You can reconize a vane pump by it’s distinctive “whine” .  If taken care of, it will outlast a gear pump.  Vane pumps come in different gallons per minute.  I will size the vane pump to match your tractor’s engine so the loader is very responsive without lugging the engine.