We use the following, Manual trans: 1/2 Redline MTL 1/2 80/90 GL1 non hypoid gear oil. If the trans leaks re-seal it. The Redline helps with the cold shifts and runs cool. The GL1 is quiet. I have found it difficult to buy GL1 in small quantities.You could replace the GL1 with 75-90 synthetic gear lube (we stock Redline). Diff: 85-120 GL5 non hypoid gear lube. We also use synthetic 75-90 or 75-120. Again it is hard to find non hypoid in small containers. Best, Carl