Hello Everyone

I am based in the UK and own a 1953 Chevy 3600 with 4 on the floor.

Looking at my owner manual it say I need Multipurpose SAE 90 oil for gear box and transmission. This term multipurpose does not appear to track back to an actual specification i.e GL-1 or GL-5

I would say the most common type of gear oil in the UK is EP90 some supplier sites say that this is equivalent to SAE 90 GL-5 which is an EP extreme pressure lubricant but some site also say it is not suitable for yellow metal bushings or bearings. I actually don’t know if my gear box has bronze bushing etc. it does say its suitable for transmissions and Hypoid usage,

I can also buy oils in the UK that have the SAE 90 GL-1 specification, these are still classed as gear oil but tend to state for manual transmission and worm boxes. They don’t mention suitability for Hypoid use which I am guessing is the differential. It says suitable for historic vehicles and tractors

https://www.ryeoil.co.uk/shop/vintage-gear-oil-90/


Thirdly I can buy from miller oils SAE 90 - GL-5 / EP90 this oil say it’s safe to use on yellow metals,

https://www.opieoils.co.uk/p-69297-millers-oils-pistoneeze-classic-differential-oil-90-gl5.aspx

Can anyone help advise me on what I actually need.

Thanks Regards Chris