I know this has all been beat to death but I'm having trouble deciding if I should use the Syn 3 in all three holes. The Forumula+ in the primary and transmission or the new gear oil that harley sells I think it's a 80W-140 weight oil.

Does it even really matter? I will be buying H-D branded oil only because it's convenient. I just wan to know what oil I should be put in the primary and transmission.

 

Yes, it has.

Only to the extent that it matters to you.

All the best,

Shane

 

So Shane what oil have you decided to use in your M8 primary and transmission?

 

I use Formula plus in the tranny and primary. You could use the net gear lube if you think it needs it. Mine shifts fine with no whine. Just did the 100 mile service on the 18 Road King.

 

Syn3 runs great. Ezpz

 

There's a specific fluid made for each hole so why not use them? As you said you'll be buying the harley brand stuff...nothing wrong with that , other than they're proud if it. Use the syn3 in the motor, formula plus in the primary and gear oil in the trans. If you've been using syn3 in all 3 holes you'll really notice a difference in shifting after the change.

 

I'll next use whatever you decide on.

 

fwiw, I'll be doing mine tomorrow,

somehow I've accumulated 5 quarts of H-D T&P oil and 2 quarts of SYN 3 so that's what going in the new motor.

 

I just ordered from New Castle Harley 5 quarts of regular oil,and the new HD gear oil for the trans and primary. They are saying the gear oil is like the redline and truth if you change your oil regularly you should not have a problem just save your receipt and mark the mileage and the date on the receipt when you bought all your stuff so God forbid there is a problem you have proof that you used Harley-Davidson product and my case I got a 2018 Road Glide special I bought it used with 4000 miles on it the bike has a stage 3 kit which was installed through Harley at about a hundred miles and when I call them to verify the oil that they put in it including finding the receipt they used 2050 regular oil not syn3 so it is really a personal preference what you rather use and my situation the only reason why I'm sticking with Harley product is until the warranty is over after that I'll probably go with whatever is convenient and that I can buy locally.

 

Also take into consideration if you are the type of person that goes on good amount long trips make sure you also use product that in case of a problem of where you're running low on oil or you need to add some take into consideration that you want to be able to pull up to a gas station and buy Mobil 1 or a Walmart or a Harley dealer that you'll know that they'll definitely have your oil