M Roadster - Manual Transmission Fluid

[GaryD]

My '06 M Roadster is now 11 years new. I only have 11,500 miles on her but I want to change the transmission fluid. When it was new I replaced the factory fill with Red Line 70W/80W GL-4 MTL gear oil (SAE 5W30/10W30 engine oil viscosity). BMW calls for ATF fluid. I am inclined to still use MTL. Any thoughts?

[wdb]

Redline also recommends ATF.


https://www.redlineoil.com/news_article.aspx?id=13

[GaryD]

Thanks. I'm still on the fence. I have one of the transmissions that had an issue with 1st to 2nd gear grinding with quick shifts at higher rpm's. I remember that changing to MTL helped a bit.