X2

dr p wrote: Somewhere there is a shirt that reads" if at first you don't suceed, maybe you should do what dr allis told you to do in the first place"

Well, if there isn't, there ought to be!!!

I certainly have... no success but leaving the control in the lift position and putting it in gear and yes once the wheels start moving up it comes. I don't blame the poor tractor, it'll lift any normal implement no problem, just surprised still, that the D14 hydraulics are noticeably more powerful.

Thanks everyone for taking time to give input.

So, what you're experiencing, is the unloader being tripped, just as Doc suggested.

The reason why you can get it to lift MORE when the wheels are turning, is because the unloader is sensitive enough that a little more speed will cause it to trip EARLIER, than if you slow it down.  by creeping along slow, the unloader will hold out to a bit more pressure, thus, it will keep pumping into the lift cylinders.

EVERY hydraulic system needs self-protection.  In a fixed-displacement pump, if you drive it into a plugged line, the pressure in that line will continue to increase until one of three things happen:

First, the shaft torque load of the pump, will exceed engine torque, which brings the prime mover to a stop... engine stall.

Second, the pressurized line, or any fitting, or the bump body, will exceed it's capacity to restrain oil pressure, and then it will fracture, thus, releasing pressure, and whatever pieces of debris that unceremoniously surrendered.

Third, the driveline between prime mover and pump will self-disengage, usually in an abrupt and expensive fashion.

Most hydraulic systems have a pressure relief valve specifically FOR protecting from each of these three fates.

SOME hydraulic systems however, have a pressure sensing mechanism that, when a pressure setpoint is reached, will either disengage the pump, or disable it's pumping, or divert it's output back to the tank, rather than to the load.

The Allis pump uses an unloader mechanism, and while it's INTENT is to be pressure-sensitive, the fact that volume of flow, through restriction of plumbing, results in the generation of pressure, proportionate to the velocity which the fluid is being pushed. 

So by slowing down the engine, the pump's volume is slower, the fluid's velocity is slower, so the unloader is able to hold on longer.

I relate very much to what you're saying about wear tear and fatigue. It brings to mind one thing I can mention here because it relates to the hydraulic pump on this WD. One time I had forgotten the control lever all the way up because the last thing I did was raise up the lift arms before I shut down the tractor (no load on the 3 pt.. hitch though, this time). Next time I went to start the tractor I thought "what? either my starter is caving or the battery nearly died" only to find out how much torque was really required to crank the engine against the force of the relief valve. It was a very good lesson for me to always check the position of the control lever, you never know with grandkids also around anything is possible.