What is a better lube, 70-90 wt gear lube or Harley semi-synthetic trans lub? The gear box is new and mated to a 93" S&S, Thanks

 

Iam thinking synthetic. Not so sure about the harley brand. the " maytags"... the rodney dangerfiels of 4 spds,....& rightfully so:-)

 

Thanks for your reply. I decided to go with Royal Purple 75W-90 synthetic gear lube. It's meets GL-4 and GL-5 requirements and has shock load protection. I think this will work better in the "Maytag" than the HD semi-synthetic.

 

Good old 50 0r 60 wt motor oil is what the manual said use . Been running big inch shovels forever and not gently tried all the wiz bang new oils and have the best performance and least issue the straight 50wt . Gear oils made the trans clunky and slow to shift , synthetic's leaked & bleed faster than government secrets and there was no change in shifting or smoothness over Dino .

Problem with synthetic's and shovelhead's is it will seep and leak from everywhere , but doesn't with dino oil . The castings on the shovels and early evo's had porosity issues , syn. oil can actually weep through the case walls and it will work it's way out around the mounting stud threads below .

The Hi tech Syn. oils are the bomb for newer machines but it can be a real pain in older iron with some miles & wear . Just a heads up ,fought this battle too many times .

Another problem with the heavier gear oil blends and the maytag's will be rougher hard shifting . That Rube Goldberg linkage and shift pawl set up on those is not user friendly for smooth fast shifting and the linkage arms & pivots wear out fast .

Do yourself a favor if you can and look for a ratchet top trans instead of the goony bird you have , they do not like dealing with big inch motors . Blown a couple of them over the years .

 

And the main drive seals are much better in the non rube goldberg aka cowpie tranys

 

I agree I put synthetic in my turtle top..big mistake, thing puked it all out in a few weeks. Straight 90w gear oil is what I'm using, might try the 50 or60w like twizted said he knows his ****.

 

You'll notice a big improvement with how it shifts particularly when she's cold and motor oil doesn't foam up like gear oil so the trans isn't pressuring itself and seeping from everywhere or blowing by the seals .

 

Twizted looks like your the shovel guy! Just answered one of my questions

 

how about some love for the "turd-top" guys - I lie the rotary tops - know why - cause you can buy them for like 150 bucks - mine dont leak - shift fine - but I have found 50W induces a little more metallic feel and clinks when the tranny is hot - since Dennis Kirk is near my house - I just use the Drag Specialties cheapo heavy duty stuff - like 7 bucks - 50W is like 6 bucks at the auto parts store - best stuff I used was some left over Honda manual trans fluid - stuff made the tranny smooth as silk - quiet - no clunks - still have it in one of my trannies after 5 years - still smooth as silk and looks clean when I sample it - like TwistedBiker - I've run all sorts of fluids in my 4 speeds and sporties - worst is 20-50W - then 50W - then 60W - then half STP:50W - then Drag Specialties stuff - then high end synchromeshg stuff - redline and others

 

I settled on 50 or 60 because it simplified carrying a bottle or 2 of oil on road trips, that it works so well is frosting on the cake. And your right I have a maytag sitting on a shelf in the shed think I did pay $100 for it, think the only reason I bought the thing was it has the longer mainshaft for the belt drive system.