Was this a problem before you changed the fluids?
Do you have a hydraulic high/low? If so you may have air entrained in it.
When you change the fluid the fel and rockshaft should both be lowered.
You might try working the air out of the system by cycling the fel up and down to the stops each end, same with the 3 pt hitch. Turn the steering wheel lock to lock several times while holding it at each end for a few seconds. Do this 5 or 10 times and see if that helps.