My 91 240 sedan's AW70 overdrive got intermittent then quit. I found one on EBay for $16.99 plus $2.99 shipping. Since it was much cheaper than others, I wondered if lacked the o ring or something. It arrived quick with the required outer o ring and bolted right up. 100 miles later, no leaks and the overdrive engages every time. I would provide the following hints. The holes the mounting bolt goes into are bored all the way through, so it might have helped to squirt some penetrating oil up there the day before. The wrench I used was a stubby 12mm.