What weight transmission oil in a tr3 with OD? I have been spoking around the internet for ½ hour and I am still not sure if it is 30 non detergent or GL4. I have always run 30 weight non detergents in my tr3s for more than 40 years—but I will say they have leaked and made noise. Now with this OD I am concerned. It sounds like both would be fine, but 30w is conservative way to go. I just see a huge difference between 90w+ and 30 weights.