Hydraulic Flow Issues with 2007 1600 WAM

[Strawwalker]

I own a 2007 JD WAM with 450 hours. Took into the dealership to spring tune up and have spindle speeds checked. They informed that after a few minutes the spindle speed to drop. They check the flow on the checked the flow on the pump and found no issues. The mechanic seems to be stumped. Anyone else have this issue with the WAM 1600? Any solutions or what can cause this?

Thanks.

 

[Hay Dude]

wrong hydraulic oil?

 

[Strawwalker]

As part of the service request to have the oil changed. I would hope they used the right oil. Anything is possible.
It's a little concerning with the service manager calls me to tell me they are stumped.