I have heard a lot about the use of 85/140 oils in Harley transmissions.I want to know is it ok to use 85/140 GL5 hypoid oils in 6 speed heli gears in Australian climates or is it too thick. How will the thicker viscosity affect the seals etc. Can anyone with real knowledge enlighten me. Regards Mark
Thank you for your reply. Do you think the thicker viscosity would be a problem in Australian winters as far as fluidity and and the oil getting to where it is supposed to go ???
In theory there should not be any problems, the only issue i can see is if the needle bearings will get enough oil to them ( i personally believe it will be ok) a thicker oil can cause shifting problems with gearboxes that have syncros which to my knowledge harleys dont. There is plenty of info on the net to do your head in for months about oils, but from my personal experiance (hi performance steet cars, and low 7 second drag cars) choose oils baised on the temps they will be seeing...because its the heat that makes oil thin, the thinner it is the faster it can flow but the less pressure loading it handles. My advise is try it, try a few different oils, no 2 motors or gearboxes are the same....
Regards Andrew
