http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=150231186527&ssPageName=ADME:B:WNA:US:1123 There is this old Roof mower on Ebay for a few more hours and I want to know about its self propulsion action. in the picture you can see a clam shell like transmission next to one wheel. (the picture that is sideways) I want to know if its one speed or more? especially can it be in gear, yet by depressing a lever, still be manually rolled backwards with out having to be shifted to neutral, i.e. for quick forward backwards trimming? I'm looking for a transmission for a newer big wheel unit I have, that I want to swap out because its transmission won't let you free roll backwards with out first having to take your hand off the handle and shift to neutral or reverse. I asked the seller buy he's never used it - just got it in a trade or something.