My dealer put redline in the tranny when I had my 1k service.I've been running it in the 07 fatty since break in, nothing but good.

 

either will be fine. But lots of us have the redline. I have it and can tell no difference between it and the mobil 1 75/90 gear oil I had in before. The dealer is just another opinion based on what his experience has been. Probably no more than any of us.

 

i went to a motocross type of place the other day and bought some redline shockpruf v-twin.and there were two varieties. one sounded lighter weight in the bottle, and one felt heavier or splashing less. that's the one i got. hoping it's the same as shockpruf heavy. am i right with this?

 

Shockproof heavy is chemically the same as the v-twin tranny fluid according to redlines website.

 

Go with the RL shockproof heavy. Its what I put in my 09 Ultra. Does great. I also put in the SE compensator and the Oregon Bike tensionor while I was changing out my inner primary to a chrome one. It made my clunk go away.

 

Save the motor oil for your motor, use the Redline.

 

I'm pretty partial to Amsoil products , but to be fair I have tried both The Amsoil 75w90 and the Redline Heavy Shockproof.
First trans change I went with Amsoil , sounded pretty good , much better than factory.
Second change with Redline , "slightly" quieter than the Amsoil.
Third change , back to Amsoil , "slightly" louder than the Redline.
This change coming up , I will stick with the Redline from now on.
Not a big difference between the two , but a slight difference , and I like the difference.
Just my observations with my 09 six speed.
Mick

 

Another vote for redline

 

I like a 50/50 mixture of amsoil and redline. It is the best.

 

Ignore the dealer- he wants to sell you what's on his shelf. Anyone who says Redline shouldn't be used in '07 & newer trannys doesn't know anything about gear oil.