On top of a complet set of wrenches, you should carry a couple of 18" adjustable wrenches-good for taking the big hydraulic lines off if needed. For instance, on my bus, it is easier to physically take the complete transmission filter off the bus when changing then try to change it on the bus-and that means loosening the two giant hydraulic lines (like 1 1/2?) and retightening them. You always want to use two wrenches so you can take the strain off the fitting with one while tightening the hose with the other. Good Luck, TomC