I have looked through my instruction manuals but I have not found details on filling the hydraulic fluid for my suspension. I check the resevior and found that it was barely at the tip of the bottom of the dip stick. I wanted to know what is the procedure for filling it. Do I do it with the engine running or off? The manual did say that it holds 2 quarts but do I have to have the engine running to pump the fluid to the rear and give me the correct level on the dip stick. What other brands of fluid are compatible?