I have used Redline Shockproof Heavy for many years with good luck; except for the awful smell when the bike gets warmed up and your sitting at a stop light. SJ Ron

 

I'm glad I'm not the only one who's noticed that smell. I was looking for leaks at my seals when I started using it

 

I tried different ones but went back to Formula plus...shifts fine...Just remember to actually change it.

 

I love Shockproof! But I've noticed the smell occasionally too. All I know is my bike shifts like butter and finding neutral is easy peasy.

 

Well you must know more than some of us, the factory manual for my 95 softail doesn't list any specs on what goes in the transmission or primary other than HD part numbers and being new to harley's I really have no clue either what goes in them.

would the 75/90 or 75/140 gear oils be the stuff to use in the 5 speed in my evo as well?

 

I use 75/140 in my Evo and Twin cam transmissions. Like stated above it quiets done the clunk, neutral is easier to find. Harley's ran a heavier gear lube in the past and these transmissions haven't changed much---just go more crowded. I didn't like the lighter oils in my transmission.

 

While the used bike I bought came with a lot of neat goodies, it didn't come with an owner's manual.

 

75/90 wt gear oil is about the wt of 50 wt oil. the 75/140 is about is about 60 wt. Your really not putting some super heavy, thick oil in the trans. Unless you have bent shift forks ,they all shift about the same. What will make the biggest difference in shift quality, is what you use in the primary. I've found that 20/50 wt oil seems to cause drag on the clutch plates. Which is why most bikes have that loud bang when putting the bike in first gear. Kinda like your shifting without using the clutch. I've found that 10/40 or 15/40 wt oil works the best for me in the primary, but some guys use atf., but say the shift quality gets notchy after a while.,,

 

I ran Syn3 in all 3 for my RK's first 50k miles and I've used HD's Formula+ with no problems but I think it's a bit sticky for the clutch so I Valvoline 10w40 non-syn motorcycle oil in the primary. AutoZone is about 25 miles closer to home than my HD dealer. I've got to believe that HD Formula+ is lighter than the Hypoid gear oils that so many people put in their Harleys' transmissions.