Tym 27hp Tractor losing Hydraulic power

[dayjd1]

For the last couple weeks I have noticed my bucket coming up slower and with my forks attached to the bucket it tends to come down when the tractor is off. Recently even if the tractor is running it still wants to lower itself. It does not raise as high as it use to and it lift capacity is much less than it use to be. The hudraulic pressure oil window at the rear of the tractor shows the oil is maybe half to 5/8 full when running or not.
Anyone have any idea what the tractor problem could be? Thanks for your help, Bill

 

[jigs_n_fixtures]

Leaking seal internally on the cylinders, or a leaking valve.