If I were you, I would take your machine somewhere else, maybe a reputable vacuum repair shop, and let them look at it. I have had several G-series machines and currently have a Diamond Edition and an Ultimate G and I honestly cant imagine your transmission needing to be replaced, none the less with a price tag of $220. I purchased my Ultimate G at a garage sale this past summer and it was in rough shape but cleaned up well, but I think that the Tech-Drive is smoother in that machine than my Diamond Edition that I purchase NIB. You would really have to abuse the crap out of the G6 to ruin the transmission. My guess is that the dealer has the mentality that a sucker is born every minute and wants to hit you with the most costly charge they can. Best of luck!