Have a '10 Ultra that I purchased from a member of this forum (love the bike)! He provided the following:
The primary oil is Mobile 1 racing 4T -
Transmission oil is Redline Shock Proof - Heavy -

My shop suggested the following:
i would go to ammsoil and use there 75-90 in the tranny

Any input to allow me to make an informed decision?

 

Any oil you use will be an upgrade from Harley's oils. If you feel your doing something good for the bike , use the most expensive oil you can find. If you want it to last until you decide your ready to sell it,then use whatever's in your budget. There really are no bad oils out there these days.,,

 

Thx big cahuna.. that was my guess, but I'm not "mechanically strong minded" ...

 

I've been running amsoil syn trans oil in my tranny for years. No foaming, no issues.

 

Thx 28INF... think some folks just have particular brands they swear by.. I've used ammsoil in all my other scoots.. so figured this wouldn't be an issue..