I have a 28 ton huskee log splitter. worked fine until: I was splitting wood and when I returned the cylinder and tried to split another piece the ram started to move slowly . I f I waited for it to make it a quarter of the way and tried to return it also returned slowly. I replaced the dent valve and no change. I am going to change the filter and the fluid. What is the process or flow chart for troubleshooting this issue?