Recently I decided to change the differential fluid in my 98' Camry. Before I drained it I wanted to make sure that the fill plug on the side could be removed. As expected, it was extremely tight, not budging when using a 12" box wrench on the nut. I was unable to use a socket wrench on this bolt due to it's location. Then I came up with an idea. I put a short length of 2x4 under the end of the box wrench and positioned a floor jack under the 2x4. After soaking the fill plug with penetrating oil, I slowly applied pressure to the jack handle and lo and behold, the nut broke loose. To refill the diff, I found the easiest way was to use a long funnel with a length of rubber hose attached to the end. It takes about 1.7 quarts.