I just put this stuff in, after changing the clutch, and this synthetic gear oil is smooth as hell. I paid $7.15 a quart at the local hot rod shop. They didn't have MT-90, but carried the purple stuff. I am really impressed, but i will see how it handles the 100+ degree temps this summer. Just in case anyone sees this around, it's nice stuff.

 

Better be certain that it is GL-4 and not GL-5. The GL-5 will slowly damage your trannie.

 

on the bottle it said it was in specs for gl-4 and gl-5. Are the gl ratings only for dino gear oil and not synthetic?

 

If the bottle says rated for GL-5 then it will ruin your soft metal synchros. Just to be sure I would call Royal Purple tech support and even then I would drain it. The only 2 products rated solely GL-4 are Red Line and Amsoil.

 

I agree. The GL ratings apply to the additive packages in the transmission fluid -- both dino and synthetic. The fact that what you installed will work for GL-5 is bad news for your trannie. I will be installing the Redline in a week or so. There is a good deal of discussion on this topic in a sticky on this site on manual trannies.

 

What i don't get is that there are probably so many clueless nissan maxima 5-spd owners who go to shops who put gl-5 gear oil in their cars. I've read the stickies but nowhere in there it said their trannies failed due to gl-5. The owner before me seemed clueless too, as he had a Fram filter when the engine needs an antiblow back filter. I bet the gear oil was gl-5 rated too when I drained it. So, if my shifting stops feeling like butter, then i should know I need to change it? The only complaint i read about was that the people's shiftign was notchy with gl-5, and mine is far from notchy. If the detergents do happen to eat my tranny, how long would it take for the synchros to be eaten to death?

 

I'm not enought of a lubes expert to know. There may be others on this site who can answer this question. My question to you: Why wait for the trannie to fail, simply drain out the GL-5 and replace it with GL-4. Then you can be certain that whatever damage that may have been done will be stopped.

 

DRAIN IT NOW!!!!!!!!!!!!

THIS CRAP ****ED MY SYNCROS!!!

by being rated for GL-5 it has wayyyyy too much detergents, i can feel every gear and shifting into 3rd takes all my muscle. dont make the mistake i did....Royal Purple is for race car teams that can drain fluids ever week, its not ment for long trem use, it breaks down too fast. When i took it out after 20k km's it was black as hell.

But hey...if it works for you, knock yourself out.

 

If it is actually rated for GL-4 then you should be fine. It will only contain the additives if it is only rated for GL-5 and not GL-4. The old Amsoil Series 2000 was rated GL-2 through GL-5, which of course includes of course GL-4.

I know the new Amsoil gear oil is rated for GL-5 but can be used in differentials needing GL-4. That is becuase the differentials don't have syncros which can be eaten away and probably shouldn't be used in our trannies.

 

According to the fella at syntheticwarehouse.com, via Amsoil dealer newsletter, they claim that their GL-4, GL-5 rated gear oil "won't get hot enough to activate the additional detergents" when used in our application. This guy could be blowing smoke, but he was familiar with both our tranny's and apparently the Sub's ( WRX, ect) have a very similiar issue. I will call Amsoil direct on the morrow and ask this directly. Will post with conversation excerpts.

 

what about royal purple 10w30 oil for the engine! I have alot of miles and looking for the maximum performance!