I have a 52 Ford 8n. After getting it running, I played with it to make sure everything was functioning before changing oils. I pulled the dipstick to make sure read end and hyd reservoir had oil obviously. It was a nasty color and needed changed. Here?s my problem. The hydraulics worked fine up and down, no leak off with blade on it before I changed oil. However after I changed the oil it started to jump as it goes up and slowly leaks off, even while running and pto engaged. I used regular uthf. Is the oil too thin, possible he dirty oil affected pump and now clean oil bypasses or what