JD 750 Hydraulic issue

[Klaibs27]

So my very worn (4400+ hours) 750 was making a heck of a racket when I started her up this morning. Up until now, they hydraulics were smooth but slow and I know I need to rebuild the curl cylinders but that's a project for another time.
The motor seemed to be purring quite nicely but I think the hydraulic pump was squealing. Everything would chatter when trying to raise the bucket or 3 point and I had ZERO power steering. The dealer flushed the screen and hydraulic system multiple times when I first got it (less than 20 hours on it since then probably) and the hydraulic oil level seems OK and it's not milky at all. Take a look at the video and let me know your thoughts?

 

[oldnslo]

Not sure where you are located but if in area with colder temps I would check the pump inlet or suction lines to see if any cracks in a hose or loose hose clamp. Cold weather makes oil thicker so any air leak is magnified and would cause pump to be noisy and system to chatter.

 

[Klaibs27]

We thought it might have been a clogged filter screen. We did a full hydraulic flush and both that filter and the spin on filter still looked good. The noise is coming more from the Selective Control Valve so we'll have to investigate further.