+1 on shockproof. I swear by it. What an amazing difference.
Just recently, my wife was having a VERY tough time finding neutral on her FLHX which had only ~1000 miles on it and the original fluids. Swapped to RL Shockproof when I did the 1000 mile service and BANG - problem solved.
My 05 flht had 33K on it when i traded it in on an 09 Ultra. my bud had an 05 classic with the same miles. We both used Amsoil for about 25k and we both within a month had transmission fluid leaking from the left side behind the clutch plates. quite a coincidence I'd say.
Now that I have 2500 mile on the Ultra, I'm switching to red line shock proof based on what I've read here and other websites. I don't think thinner is better in this case.
thanks to all who have taken the time to comment so others can be better educated.