So I've been draining the w56-e gear oil in my 1993 pickup and not that much oil has come out. I know it's capacity is around 4 quarts but almost half that has come out. Before I drained it the level was up to the fill hole. Any reason all my oil isn't coming out? Does it need to be jacked in a certain way? Thanks

 

The trans sits on an angle tipped down. You will need to jack the back of the truck up.