I was having the same problem till I realized I was doing it wrong. It doesn't fit up flush with the seats, but instead back against the bumper. Put the front in to the angled slot push it down till it hits the tire then pull back smartly towards the rear. It looks dumb and leaves exposed metal at the front so I just put it back up in the top position. If I ever need the extra room I'll just toss it in the garage and throw a blanket in the back.