This is sailsam again. When you say you found a nut and bolt on the garage floor was the "nut" a sort-of cube shaped piece (rather than a hex nut), black on 5 of the 6 surfaces and silver color rough on the sixth surface? If so, it wasn't a nut, but the piece that broke off the casting. If you can, get Terra Trike to replace the derailuer with a better one. The one that came with my Traveler was a mine was a "Mezzo MicroShift". If they insist on using that make just go to a local bike shop and get a good one. My Shimano Altus cost only $48.49 installed. I figured that 1. avoiding not being able to use of the trike for the week it'd take to get here AND 2. avoiding getting another breakdown soon after installing the replacement was worth the cost.