When brush cutting with MF-1100 recently, I noticed the 3 point lift was slow in responding and wouldn't fully lift the 7' cutter. The lift worked fine when I started. Noticed the problem after 3-4 hours run time. I thought it may be the main hydraulic filter so I changed it. That did not affect the problem. The lift will fully raise slowly with no weight on the arms or with a relatively light back blade attached. Position control works - just slowly. With the lift raised if I pull the unloading valve or shut off the engine, the lift drops quickly; not a slow leak down. Steering, brakes, remotes, MultiPower, PTO clutch are all normal. No strange noises. I have a shop manual. Been reading and trying to understand how the system works. I have some things to check inside the inspection plates. Was wondering if you folks may have suggestions about likely cause and what to check first. Appreciate any help and suggestions you can offer.