hi guys i want to put the redline shockproof in my 2015 rgs but i see there is light-med-and heavy 75-140 which one is better for less noise/clunk on shifting? thx

I believe it's got to due with ambient temperature. Living down south, I use heavy all the time.

I run a 75/90 with Heavy Shock

I use redline with shock proof , don't recall the viscosity , but don't be deceived by the numbers , trans oil viscosity is rated on a different scale . 90 is like a 50w motor oil and 140 is like a 60w or 70w motor oil

I was just reading on the RL site. It says their heavy weight gear oil 75/250 flows the same as any 75/90 WT gear oil. It also says their VTwin tranny oil with shock proof is the same thing as their heavy gear oil with shock proof. They only sell one VTwin tranny oil. (Run what ya brung.) It also stated their light weight gear oil is for smaller gear cases ,like on the 2 stroke dirt bikes and Racing cases.
With that being said, I'd think even running their super light weight gear oil with shock proof is better than using
Harley SN3 20/50 in the Transmission.

thx for your replies i ordered the heavy shockproof