I want to run 75/140 in my SG tranny this summer. I have always had Mobil 1 in all three holes. But nobody has the Mobil 75/140 here . I've been told the Walmart SuperTech is basically same stuff. Does anyone know if the synthetic superTech stuff is any good. I can get it in both stores here and it's a good bit cheaper than Mobil 1 anyway. Thanks

 

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Hmmmm! Bump!

 

Enqiring minds want to know ! Come on internet experts fill us in?

 

this would be a no-go. SuperTech 75W140 is a GL-5 rated gear oil. You can only use GL-4 rated gear oil in your tranny. GL-5 is corrosive to soft metals . GL-4 is fine with soft metals. Mobil 1 GB oil is also a GL-5 rated oil.

 

thank you, glad I asked. Even Mobil says not to use the GL-5 gear oil in harley, just the 20w50 I have been using.

 

I was under the understanding that H-D 6 speeds did not have any soft materials in it? If that's the case, a lot of Redline ShockProof users are doing harm to their trannies as it's a GL5+ rating ...

 

Exactly, Mobil 1 gear oil is a GL5 and a lot of people are using it.

 

Is there anyone here that has had transmission failure from using GL5 rated gear lubes?
Can you provide proof that GL5 will harm the transmission?

Take a look at the oil forum.Many of us here are using GL5 rated lubes such as Amsoil,Mobil,etc-.

 

I have Walmart 75w140 for the last 3 changes... no issues... i have not seen any difference between, Formula plus, amsoil 20w50, movil 1 20w50 v twin or Walmart 75w140...70000 miles on my 07... it's full syn just like Mobil 1 so i went ahead. By the way... when the dealer changed my inner primary bearing at aroud 45000 the tranny looked impecably clean... mechanic said the saome...