That's just a hydraulic strainer, not a regular filter. It needs to washed out several times in a bucket of gas until it's completely clean. The important thing is making sure the gasket wasn't damaged upon removal. Only the hydraulic filter and 0-ring inside the filter cannister needs to be replaced. If the cannister itself doesn't leak you may be OK not replacing the 0-ring. Due to the age of these machines you will start having one leak after another so it's best to just replace anything that looks old when the fluid is drained. The majority of the mechanical parts used for these machines can still be purchased and was used on other brands of equipment. The Prime Mover company didn't make the parts. The only thing I couldn't find was the hydraulic pump at the rear of the machine. But the pump IS rebuildable because I just had mine rebuilt with a new spline shaft and pressure plates for 600 dollars. As far as I know these machines were only made during a 10 year period during the 80's. Mine was produced during the first production year and has the older John Deere 3164d engine. In the later years they started using the 3179d engine with the only difference being 10 more horsepower.