I was trying to change my diff fluid in my car tonight, but cannot get the fill plug to open. Luckily I opened tried to open the fill plug before opening the drain plug, or I would be in really bad shape. I used a big ratchet, tried hitting the ratchet with a hammer, but it would not move. I even used liquid wrench to no avail. I didnt want to strip the screw (i dented part of it from pushing so hard). Any ideas, the car was on ramps, so there is no room for a cheater bar. I may just take it to the transmission place to do it, but before I do....Any suggestions?