It first popped up in the 2008 Rocket Touring motors which were fully updated, then followed by the mid 08 and 09 standards and classics, which came fully updated, then well the ones who had the update kit starting having them on occasion. I think it actually changed because of the detent wheel diameter change when it was improved on. I think the thought wheel diameter smaller less wraps needed to hopefully apply the same spring pressure. Oh and not taking in mind the difference in the rolling resistance of a solid detent wheel abd one that was actually a roller bearing. At the quantities most likely purchased verses the QA testing quantity required makes it hard to say bad run, or runs. What about and where it was assembled? (Was their beer for lunch properly chilled? Do they even drink beer or are we talking some type of ferme ted rice )Then hey the differences in how it is used. Say like are you the guy that pulls up to the stop light then sits there and stomps down 3 or four times to get her down to first without giving the transmission some time to tumble and line up? Or do you down shift as you aproach the light i case you also need the engine to brake or accelerate abruptly? These are some of the things one should thunk on when trying to pin point what caused it. Yes lots to think on when trying to figure what is the difference between the two. Oh and well if they were bad why is there not bunches and bunches of failures ?