What transmission fluid do you guys recommend for a Series 1 Manual?

 

Common recommendations areFord Motorcraft XT-M5-QS
Eneos 75w90
Redline MT90
Avoid GL5 oils, GL4 only.

Don't forget the diff needs oil too, any 75w90 is fine there.

 

IIRC the Eneos is also a GL5 but BHR has been using it with success.

 

Brand probably doesn't matter as much as long as it is GL-4 for the transmission. Rear diff is less picky therefore GL5-rated 75w90 oil will do. IIRC additives are not required.

 

Motul Gear 300 is also good. You can use it in both manual trans and diff as it is both GL-4 and GL-5 compatible.

 

I used a few others successfully as well, but funny how some people will see that vendor name tied to it and then; well, it must be ok then 😑

It’s an honest mistake I suppose, but kind of ironic to see that posted and then tell everyone not to use GL5. 😂
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I was resistant to this new Redline oil, but a few people seem to be having favorable results

https://www.rx8club.com/new-member-f...-tried-272904/


I never was a fan of Redline MT90 though and generally try to steer people away from it.
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I came across the new MTL LV from Redline. I think it's a 70W. Pretty thin but read good experience thus far.
I too am not a fan of pure MT90. Instead I do a 50/50 concoction of MT90 and MTL.

 

I'm using Amsoil and it works well for me.