You can certainly use it in all three holes if you like. Some folks prefer to use a gear oil in the transmission such as AMSOIL'S 75/90 Severe Gear. I am sure Mobil and Redline also have a gear oil. Harley has a gear oil that is petroleum based which works well also. Choices, choices
Yah I use 3 different viscosities... 20-50 for the engine, 75-90 in the tranny and 10-40 in the primary...all Amsoil. Maybe a bit obssessive but it all costs the same so why not.
Redline heavy duty shockproof in the tranny, and you'll never, ever go wrong. \\; That trans will outlast your motor. \\; Any good syn 20-50 changed regularly will serve the crank, and the primary could be whatever.... I use the MOCO Primary just cause it's easy to get, find, and have on hand. \\; CCRyder
i agree you should use gear oil in the tranny for best results ii use severe gear amsoil
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since i changed to amsoil my tranny is quiet and \\;shifts better now