I have noticed that when I change my transmission oil that it ISN'T dirty. I swear that it looks as good as the day I put it in. I have been using F+1 in this bike (02 Road King) since I got it three years ago. I change all my lubes every year. I'm planning to switch to the Specto GL-1 as soon as I get it, because of what I have read in this forum. My question is do I have to change the trans lube every year or can I extend my change intervals. I only ride approx. 2000-2500 miles per year (I know it's not much). Your thoughts please.