Heres an AMC wild thought. Jack up the rear end, spread out the cardboard under the car, and then run through the gears for several minutes, or just let it run in place. Of course use all the safety steps so WE don't lose it into the garage or back yard swimming pool. A good cleaning underneath might help before but shouldn't be needed if it leaks this much. It's not pushing it out the filler tube when under a hot load and the dip stick is the right one. Just checking. or length of tube. Sign up for Internet Service under $10 dollars a month, at https://signup.mybluelight.com