I have a Champion 22-ton wood splitter. A few days ago it started to not split the wood. The cylinder would extend and retract but when it hit the wood it stopped the ram and wouldn't split the wood. The motor never bogged down or stalled. I removed the pressure relief valve and cleaned it. Removed the spool and cleaned it. Reassembled and the ram would not retract anymore. Put a brand new spare Control valve unit on it in case I had somehow messed up something in the spool and still can't get the ram to retract. Anybody ever experience this problem and have any ideas what my problem might be?