transmission replacement

I hear a front-end scraping type noise in my 2000MT 215K miles Insight, especially in lower gears, both while accelerating and coasting. I have no shifting problems or anything that may indicate transmission is bad but my mechanic states with certainty based on the noise alone, the input shaft...

Well we got a used transmission from the Insight people (Flamboyant) in Ohio, and a garage that is going to help install it! now we would like anyone who has attempted this to share advice and personal stories, anecdotes, mistakes, lessons learned, whilst attempting this proceedure... any...