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qqzj · 07-25-2017, 08:16 PM

I am going to put Motul 300 into both my trans and diff. However, I read an article on oils recently:

http://uploads.tapatalk-cdn.com/file...nsaxle_oil.pdf

One of the comments scares me a bit:

When we use a GL-5 product in a transmission that requires GL-4, we normally find 2 to 4 times as much copper in the used oil as we would with a GL-4 product (with used oil analysis). Eventually the synchronizers wear to the point that they no longer make contact with the other half of the cone, bottoming out before stopping the opposing gear.

We know the trans oil in 86 is spec-ed as GL-3, which has less EP than GL-4. So GL-5 oil is going to eat away our transmission even quicker? Since Motul 300 is both GL-4 and GL-5 compatible, I am kind of confused. What does it mean to be both GL 4/5 compatible? How does Motul managed to do that? Is Motul 300 is going to destroy our transmission quicker than OEM? Any advice will be greatly appreciated. Thanks.

PS: Another scary comment:

You need to realize that an oil with GL-4/GL-5 on the label is a GL-5. It is not appropriate for synchronized transmissions.

07-25-2017, 08:16 PM	#1
qqzj Senior Member Join Date: Sep 2013 Drives: MDX, Camry Location: SF, CA Posts: 399 Thanks: 54 Thanked 69 Times in 44 Posts Mentioned: 3 Post(s) Tagged: 0 Thread(s)	Any UOA for manual transmission fluid? I am going to put Motul 300 into both my trans and diff. However, I read an article on oils recently: http://uploads.tapatalk-cdn.com/file...nsaxle_oil.pdf One of the comments scares me a bit: When we use a GL-5 product in a transmission that requires GL-4, we normally find 2 to 4 times as much copper in the used oil as we would with a GL-4 product (with used oil analysis). Eventually the synchronizers wear to the point that they no longer make contact with the other half of the cone, bottoming out before stopping the opposing gear. We know the trans oil in 86 is spec-ed as GL-3, which has less EP than GL-4. So GL-5 oil is going to eat away our transmission even quicker? Since Motul 300 is both GL-4 and GL-5 compatible, I am kind of confused. What does it mean to be both GL 4/5 compatible? How does Motul managed to do that? Is Motul 300 is going to destroy our transmission quicker than OEM? Any advice will be greatly appreciated. Thanks. PS: Another scary comment: You need to realize that an oil with GL-4/GL-5 on the label is a GL-5. It is not appropriate for synchronized transmissions. Last edited by qqzj; 07-25-2017 at 08:27 PM.