I'm sure no one has ever talked trans oil here, so here goes. I want the best lub I can get for my trike. Harley recommends 20w-50 for the trans and a lot of people here use Redline 90w-140 and say it works good and makes the trans quieter. Why would anyone run 90w-140 when the manufacturer recommends 20w-50? You could add a half cup of sawdust and it would also run quieter but I don't want to do that. Yes I would like to have the trans run quieter but not sure about the 90w-140. The guy I bought my trike from always ran synthetic oil in all the holes but the last time he had it serviced he didn't use the synthetic as he was selling the trike. After a few hundred miles I changed everything back to synthetic 20w-50 and the trans was quieter at first but not so much after 2000 miles. With the 90w-140 I would be concerned the heavy oil may get into the tight tolerances of some of the parts. Can anyone tell me why I should run 90w-140?