Any oil which meets the specs in your owners manual will be OK. Do your own due diligence so you can make your own choice based on what's available to you, locally.

 

The primary only need to be wet. There isn't the same factors in the primary as the motor/tranny.
Personally, I've used Mobil1 75-90 in the tranny and dino 20-50 in the primary for 35K miles

 

Amsoil 20W-50 engine
Amsoil 75W-140 Severe Gear tranny
Amsoil 20W-50 primary
Amsoil #10 Shock Therapy Forks

Thinking about trying Redline Shockproof for primary and tranny next service

 

I did a study on Harley primary case oil, and transmission oil. This was for my 2002 EVO . They are selling 70/140 gear oil in Harley containers caller Harley Davidson primary chain oil and Transmission fluid . I even checked the viscosity , same thing . They sell it in synthetic also . For my engine I run Castrol 20/50 ,non synthetic.

 

I use HD Syn3 in all 3 holes. If it's good enough for CVO's, it's good enough for my Dyna.

 

Mazola