I am figureing the GL = Grade level. Some people said yeah you can and other say no. I am asking if anyone knows anything more in deapth about this. The dealership said the synthetic will not be good. They dont know if our trannys cross over to GL-5. What th f--k? Can anyone help.
This is for the gear oil!

 

I've tried both. GL5 first and then switched to GL4 after reading up on the Max specs. I had quite a few missed shifts with the GL5. It seems that the GL5 is actually too slick for the sycro's in the transmission to mesh while shifting. I tried Amsoil in both cases. The GL4 shifts much better and feels buttery smooth. Takes about 5-6 qts to change it out. Good luck!!

 

Short answer:
Conventional oils - No way.
Synthetic oils - Maybe

 

DON'T USE GL-5

http://www.motorvate.ca/mvp.php/800

 

Yep, don't take a chance--DO NOT USE GL-5 AT ALL.

If you're looking at gear oil which is synthetic and claims to meet GL-4, ensure that it DOES NOT MEET GL-5, or if it does, ensure that it has a notice saying it is safe for "yellow metal" or brass synchronizers.

Good synthetics that are tested include Amsoil's GL-4 gear oil, and Redline MT-90. Both are popular with Maxima enthusiasts, and you hear about Redline MT-90 producing better shifting from time to time. I've personally tried Redline MT-90.

 

I've run Valvoline and Mobil in synth and regular GL-5/GL-4/GL-3. No good on any of those. Redline MT-90 was good, but expensive.

Now I've settled on Napa GL-4. Better than Redline (smoother, confident shifts, wherease Redline was just smooth) and much cheaper. I think the Napa has a better feel when you snap from neutral into gear. Perhaps the Redline was too good and made it feel buttery and slick.

Jae