May not be the tranny. I have gone through threw three bikes I bought with same complaint, all have been the front bevel gear box bearing and the main output shaft bearing gone and I mean gone.. All bearings, seals, gaskets and O ring about $350.00. I did not have to pull motor either. the bevel gear box is tricky to get out and back in , but can be done. Spent half a day getting out, half day to replace all the bearing and such, and a day to reassemble.. no tranny gears replaced..
Live to Ride
2003 Vulcan VN1600 Classic bags
2007 Vulcan VN1600 Nomad