Hi Guys, I just bought a new forest trailer with loading arm. Not so new, and full of dirty oil from an old machine (demonstrated?). My question is how do I replace the oil without contaminating my new tractor? I guess I could pump all cylinders, with the return going to a bucket, then reverse the leads, and pump the cylinders closed. Then top up the tractor oil with new. Another idea would be to have an inline filter on the return to tractor. Any ideas?