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question on AC919 hydro transmission

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We purchased a AC919H recently. The buttons on top of the rear hydro unit that allow the tractor to "freewheel" are essentially rusted in place. We applied WD-40 and let it soak. We got the pins to move down to allow us to freewheel the tractor, but now we are ready to use the machine and the pins are stuck in the down position. Can anyone help us? Can we fix these existing valves? Thanks! Tom

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After the hold down plate is released, the valves may pop up by themselves after the engine is started and the pump develops pressure. If they don't, use some PB Blaster (much better than WD-40) and gently rotate the valve tips (buttons) with pliers.

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Thanks, Herb and Dave, for the advice. Our can of PB Blaster ran out 2 days ago. Time to stock up? We started the tractor and the engine began to noticeably work as I released the foot clutch (which engaged the belt to the hydro unit). Will I damage anything if the buttons don't pop up? Or is the pressurized fluid simply squeezing through a relief valve somewhere, causing the engine to work? Thanks again, men! Tom and Peter Feldpausch

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Are you saying that the engine starts to "work" but the tractor doesn't move? From time to time I will forget to release the valves on mine and the tractor doesn't move, but the engine doesn't "work" either. Make sure the parking brake is disengaging all the way, and the PTO is off. Do you have hydraulic lift? If so, make sure that's in neutral. Change the hydraulic filter and check the fluid.

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