I did this last summer with the Stromberg unit BigDon provided a link for. It was very simple as I used my floor jack and a 3' 2x6 I had laying around. The Stromberg was the exact measurements as my 3-step unit. First I raised the jack with the board on it so it was under the unit. Loosened all 4 bolts, removed 2 then the other two. Released the jack slowly to lower it, slid it back and lifted the old unit off. Install was the reverse of it. Without a helper the jack made it very easy and was done in less than 30 minutes. One of our best mods.