Your thoughts on this?

Joined
Oct 9, 2004
Messages
11,358
Location
Cincinnati, OH, USA
If you're referring to GL-4 vs. GL-5 in manual transmissions/transaxle, it is possible to have a fluid that doesn't harm anything, but is TOO slippery for the synchronizers to work correctly. I had this issue on my xB with RP 75W90 GL-4/-5, it was sifficult to shift without grinding gears. Straight GL-4 fixed it.
 

sjd

Joined
May 2, 2008
Messages
21
Location
Ontario, Canada
So I will weigh in because I'm the one I'm that Bill is trying to argue against. The argument is this: Mazda recommends GL-4 fluid in the transmission. Some of us use GL-4/GL-5 recommended fluid for better protection/performance, in my case Motul Gear 300, and a lot of others think we're wrong. I am of the opinion that the quality of the fluid means more than rating. I have used the Motul Gear 300 in my 2010 MX-5, which also called for GL-4, for 120K and 8 years without issue.
 

Bill_W

Thread starter
Joined
May 24, 2009
Messages
305
Location
So Cal
Originally Posted by simple_gifts
Seriously, meaningful thread titles can help us all
Will do better next time, you are right.
 
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