Drained all the Harley Syn3 out of my Heritage Classic this weekend and went back with Mobil One V-Twin and 75-140 Gear Oil in the tranny. 5th gear whine now gone and bike runs fine.

 

Just wish we could ride here in Ind....Alot of oils are really good and I dont think u can go wrong with, mobil although I dont use it yet, still in warranty...

 

Here its a good oil, along with Amsoil and Lucas. Running Amsoil 75-90 gear lube in tranny, thought this should be heavy enough.

 

As long as you run apropiate oil, it does not have to be HD oil. It won't effect your warranty. I am a wrench at a dealership. We don't taste test your oil to make sure it is HD oil.

PS I never run 2050 in my trans, but that is just me. Fords use auto trans fluid in their manual trans, so it isn't a new thing with using "thin" oil in a trans.