Gear Oil service

For GL 5 suitable for use where oil to GL 4 is required too. I wouldn’t use it in the gearbox, diff yes.

I appreciate that you would not use it but it does state ‘Recommended for use in applications requiring–API GL-4’.
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Recommended by the people selling the oil… :joy: :+1:

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Indeed, but I was commenting on the above.
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Which in the UK, is as elusive as Mazda’s own IS long life gear oil.

What might be easier for a user going that path, is the Castrol Transmax 75W-90 GL4, given it says on the spec sheet (and bottle) ‘Ford WSD-M2C200-C, MB-Approval 235.72’
source: Castrol Classic Oils Shop — Buy Castrol Multivehicle 75w90 - manual transmission oil
As if on one looks at the actual spec sheet of the Motorcraft XT-M5-QS, it has a specification number WSD-M2C200-C, i.e, the same as the Castrol one above
source: https://www.motorcraft.com/us/en_us/home/our-products/chemicals-and-lubricants/transmission-fluid/full-synthetic-manual-transmission-fluids.html

Not also though, the Mazda IS long life gear oil ISN’T 75W-90, but 75W-80, as discovered by my own communication with Mazda UK, when I questioned a part number they gavve me was for 75W-80, given in the manual if says 75W-90 (GL4) can be used if the Mazda long life gear oil IS cant be obtained.
This was my response from Mazda (one of a chain of emails):

'Good afternoon

Thanks for your response.

I can confirm the vehicle should have 75W-80, however, if you cannot obtain 75W-80 then 75W-90 can be used.’

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By coincidence, the Castrol Transmax was exactly what I’d ordered from Opie after hunting for a GL4 in the correct viscosity.

The difference has been fantastic from the off. The gearbox has now had a good flush with a couple of other types of oil but this Castrol seems to be the stuff. Even the blurb states “Used successfully as a problem solver for low temperature shiftability issues and in the manual transmissions of a number of manufacturers as factory fill”.

The car currently being used on a 100 mile run so will report back on hot performance (as hot as it could get on a wet day like today!)

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