I use the Redline shock proof in my tranny. Tranny oil takes a different type of beating than engine oil. It stands up better to the shearing forces in the transmission.
The Syn 3 or Mobil 1 stands up to the high heat of the engine and is primarily designed for engines.
The shock proof trany oil from Redline comes highly rated throughout Harleydom. I used to own a Transmission shop.
I use Harley's +P in the clutch. It's designed for the clutch which has different needs and operating temps from the engine and tranny.
BUT YOU CAN USE MOBIL 1 for V Twins 20-50 in all 3 holes. Some engine oils (but not syn 3 or Mobil 1) have additives that are not good for the clutch.
Redline is more expensive than Mobil or Syn but after spending close to 20 g's on your bike why skimp on a quart of oil?
After reading the info available here on the forum and discussing it with the lead mechanic at my dealer, I decided to use what I described above. And I'm still using Harley dino 20-50 in the engine but I'm likely to switch to Mobil 1 V-Twin 20-50 for the engine.
Read up on the subject matter here in this forum.
That was me 40 years ago
My how times have changed
I think therefore I am (Cogito Ergo Sum) Descartes
I ride therefore I am (Veho Ergo Sum) JPR
65 Italian scooter
66 305 Rice burner; NO PROBLEMS
67 650 English Bike; MAJOR PROBLEMS
1968/XLCH - lots of mods; loved it for 11 years; NO MECHANICAL PROBLEMS
2012 Heritage 103 Rush 2.0 pipes MAMBO #5
bought all brand new except scooter
There's a picture of the sportster after all the mods in my images file.