I just bought a G1000 Vista that makes a pretty good clunking noise when backing up. It is quiet going forward. It must have a bad reverse idler gear. My vista parts book lists some 20- numbers for an updated idler gear and has a note written that says see service bulletin #100-350-04. I'm guessing the original reverse idler gear is known for failure? I haven't been in any big MM transmissions, but I know on the smaller ones the reverse idler can be removed without disassembling everything. Would anyone have a copy of the service bulletin? Or any insight on doing the repair? If it's a double split job, it's probably going to go on the back burner, but if I can swap the gear though the shift cover, I may have to do it so I can play around.