it's the same scale..... 70w/80 is waaaaaaaay thicker than 5w30.
No it is not. 10w/30 engine oil is approximately the same specific viscosity as 75w/80.
Please do not post speculation as fact. It only serves to confuse. Please check your facts before posting in such a deffinite manner.
gas engine
oils are rated on the "S" scale (i.e. SA,SB,SC,SD,etc) with each higher
> letter superceding the previous rating. (diesels are the same,
except using
"C" (C for Compression fired) instead of "S" (S for Spark fired). gear oils
> are usually 50w or thicker and are rated on the "GL" (for Gear Lube) scale.
> the MUA tranny and xfer case use 5W30 engine oil.
>
Quality standards used above are those set by a trade body called the API. Viscosity standards are however expressed in terms of different scales for transmission and engine oils and these are governed by the SAE. It doesn't take a brain surgeon to check that these are the facts. For instance, and because their products appear to be held in high regard, this is a section copied from their web site:-
START MTL® Manual Transmission Lubricant a 70W80 GL-4 gear oil (SAE 5W30/10W30 engine oil viscosity) designed for use in manual transmissions and transaxles. Provides excellent protection of gears and synchronizers and its balanced slipperiness provides a perfect coefficient of friction, allowing easier shifting.
END
Huw