I've never done a 518 before, but it should be pretty similar to the 727 untill you get to the over drive unit. I read somewhere once that while rebuilding the overdrive unit it takes a ton of pressure to get it back together, hundreds of ft. lbs. I bought my rebuild kit from napa for $70 and that came with EVERYTHING, a majority of it I didn't use tho because I didnt' feel like replacing all the seals.