I have an old fisher speedcast plow with the pump that runs off the engine by belt. I have been using dexron 3h but i want to switch it up. The longer i use the plow the slower it gets until i have to put it into neutral and rev it up to get the plow to come up. Anyway i am getting new hydraulic hoses made so i am going to flush the system and i was going to try the S.A.M plow fluid. It seems like people like it. The thing i see with plow fluid is that even name brands like boss and fisher all seem to be around the $10 per quart range. I was thinking of maybe trying some jd hyguard. idk. the plow works great when its first used. Im guessing its because the oil is thicker then as i use it it heats up and thins out. the old pump is probably worn out as well. so anybody if with plow or hydraulic experience could chime in as to a good oil to help stop the plow slowing down. Thanks