X475 whining

[x475owner]

When I raise or lower the deck on my x475 and hit the top or bottom, the pump whines. Same thing happens when I turn the wheel and hit the end stops. And in the past the steering wheel used to keep turning even after tge wheels hit the end stop, but the whining just started recently. I have a lockout valve because I install a snowblower in the winter.
Fluid level is full. I've got about 750 hours on it. Thoughts?
Thanks in advance.
Craig

I should have posted this in the John Deere section but hit post before I realized.
Is there any way to move it?

 

[Deere Dude]

Same thing happens to mine so I will be following.

 

[Gator6x4]

If I raise the mowing deck on my X495 and continue to hold the lever after it reaches the top up or low down positions it will whine also. That is the pump complaining about being deadheaded. When you hear the whining noise, release the lever instntly.

 

[dstig1]

Actually it is the bypass valve making the noise, but the question is why it has changed. You might actually have better luck posting in Hydraulics subforum as there are some good experts there. Could be bad/stuck bypass??? Dunno