4300 Rockshaft Problem

[gulfofmexico]

Recently, I purchased a 2000 JD 4300 off eBay. I bought this particular tractor because it had a grapple which works great. Here's the problem. The rear lift does not work properly. The linkage is hard to push or pull and the three point hitch moves up or down real slow with little movement. You can tell the previous owner had never used the three point hitch. Maybe this is the problem. It appears to have plenty of hydraulic fluid, I lubricated everything, checked the inline filter to the left of the seat. It is still hard to work with. Almosts bends the linkage when you adjust up or down.