ATF and HD Primary/gearcase

[hk33ka1]

I have also heard of people running ATF in big twin primaries. I think most ATF is about a SAE10? So I don't know if it would be the right choice or not. I think Bob said the HD Primary or Sport Primary fluid was about a SAE30 weight?

I think ATF would be too thin for a big twin tranny as a 90 gear oil is what the factory specs. Most oil companies tell you to use their 10W40 in the primary and a 75/80 W90 in the transmission.

I have been using Amsoil AMF 10W40 in my primary for a few years with no problems. I have also been using Amsoil Series 2000 75W90 or 140 in my trans but something like MTL would probably work great in there too.

 

[hotroadking]

I've heard people run ATF in the primary and the gearcase, however Harleys are Manual trans and gear boxes.

Is there any problem with ATF in either primary or gearcase of the trans?

I would think you'd want to run a MTL and I think that's what Redline offers.

 

[Tnford27]

I recently bought a 2004 FLSTCI,it now has 800 miles on it. I talked to the service manager at my Harley dealer and he said that they put 20w-50in all cavities,so that's what Im going with. By the way,I chose Mobil1 v-twin fully syn.