Oil Grade

[1550vt]

All across any HD forum you will find people as passionate about this as they are what oil they run in the motor. I say...work what works for you, but will a make a couple of comments. I do think that the MOCO no longer recommends the use of Syn 3, or any other motor oil in the transmission and they must have a reason. They now use a Formula + in both the primary and the transmission. I look at it this way. The engine itself has a few gears, but most moving parts in there slide on some surface or ride on bearings. The primary is not unlike an automatic transmission having chains and clutches...no gear engagement. Lots of guys run ATF in there or just about any grade of light oil that does not have friction inhibitors. The transmission is full of gears and other stuff that bangs around back-n-forth under some pretty severe stress and it demands another kind of lubricant that can stand this sort of stress. I simply ask, would you put motor oil in the 5-speed gear box in your Porsche or favorite pick-up truck. I think the answer would be no way.

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[frenchbiker]

Originally Posted by 1550vt

All across any HD forum you will find people as passionate about this as they are what oil they run in the motor. I say...work what works for you, but will a make a couple of comments.

I do think that the MOCO no longer recommends the use of Syn 3, or any other motor oil in the transmission and they must have a reason. They now use a Formula + in both the primary and the transmission.

I look at it this way. The engine itself has a few gears, but most moving parts in there slide on some surface or ride on bearings. The primary is not unlike an automatic transmission having chains and clutches...no gear engagement. Lots of guys run ATF in there or just about any grade of light oil that does not have friction inhibitors. The transmission is full of gears and other stuff that bangs around back-n-forth under some pretty severe stress and it demands another kind of lubricant that can stand this sort of stress. I simply ask, would you put motor oil in the 5-speed gear box in your Porsche or favorite pick-up truck. I think the answer would be no way.

I have no problem using the same oil in the 3 holes (Amsoil 20W-50). Actually, my bike runs cooler and shifts smoother. If you feel more comfortable putting tranny oil in your tranny and primary oil in your primary, do it.