MY GIRL FRIEND HAS THE DYNA AND WANTS TO PUT SYNTHETIC OIL IN THE TRANS. BEEN RUNNING ON REGULAR HARLEY TRANS OIL SINCE NEW. IS IT WISE TO DO THIS. WHAT IS RECOMMENDED FOR THE OIL CHANGE. NOT BIG ON HARLEY OIL. I HAVE AN 08 STREETGLIDE AND USE MOBIL ONE 20-50 IN TRANS,CRANK CASE AND PRIMARY. THANKS FOR THE INFO, KB