If you google "GM Synchromesh" and check out bitog, folks are saying that it appears to be lighter than 75w-90, based on viscosity measurements when compared to 75w-90 gear oil. So it may NOT meet the requirements of the trans.

Other folks also have claimed it resolves notchiness in their cars whereas the Amsoil 75w-90 gear oil didn't cut it...

So choice is yours...

 

Watch out with the Redline MTL. I used that in my Tacoma for a while. At first it was great, but about 8 months to a year later, the shifting got very much worse. I switched to a different fliud, and it shifted good again. I did some research, and apparently the MTL likes to shear and thin out over time and makes shifting a lot more difficult as the fluid ages.

I don't drive a lot of miles, so it was probably only about 6K miles later after putting in the MTL that I noticed the negative difference. If you do some research on MTL on various car forums, you'll probably find a lot of other people who have said the same thing.

The thing that worries me though, is that the Tacoma trannies are not at all finicky about fluids. If the fluid made that thing notchy, I can only imagine how noticeable the difference would be on our G35 6MT's which are notchy to begin with and also very finicky about the fluids that we put in them.

 

I bought myself some Royal Purple and had that done at 50k km's. . . now at 56k and still feeling good. I drift the G regularily at the track as well. . .

 

I wish someone had a straight yes or no on this one. Id really like to put the gm stuff in there since I know how well it works. as it stands its between the amsoil and royal purple. also, how hard is it to change the fluid on these cars? I can change my hondas tranny fluid pretty well, is this going to be harder or easier? anyone know?

and thank you all for your help

 

Redline makes track products, so the fluids need to be changed out much more constantly than anything else. Some people don't even run their motor oil for 3k miles...

I've been using Motul, and so far, it seems to be great. Changing the tranny fluid in the G is pretty much exactly the same... get a good pump and you're fine Just remember this car has a rear diff too.

 

I would use the Nissan oil. I changed both the 6MT and rear differential with Royal Purple and when the temperature is below 50 degrees, I get a high pitch whine until the oil warms up. I will change it again in the fall with the Nissan oils. I had no problems before with the original oil.

 

from what im reading elsewhere it seems that the amsoil is going to be best since of the better cold weather performance compared to the redline and royal purple.

 

so this is what I just ordered
Transmission: https://www.amsoil.com/storefront/mtg.aspx
4 Qts

Differential: http://www.amsoil.com/storefront/agl.aspx
2 Qts

will let you guys know how it turns out. Is the tranny and diff change procedure pretty straight forward?

 

ok, so here's the final update. I changed the fluids out with the stuff in the above post. The transmission has noticeably smoother shifting now. The "notchiness" is still there from first to second and from second to third but not near as bad as it was before. The process was very simple and straight forward. For those who havent done it, it is a simple process for even the amateur mechanic.

 

So I assume you're relatively happy with the change of the trans shift quality? It's just too bad that it didn't totally eliminate the notchiness..

I'd be curious if you see a slight improvement in gas mileage, given you also went to synthetic in the differential..

 

yeah its a lot better than before

 

Actually GM Synchromesh is not good for Hondas and Toyotas at all. I'm not sure about Nissans. This is because these transmission consist of components made of brass. GM Syn is known to eat away on brass components.

 

I used a 1/2 MTL and 1/2 MT90 mixture and it works wonders. A little smoother than stock during the winter months but so much smoother in the summer months. I can be going 25-30mph and shove the shifter into 1st without grinding...an impossibility with the stock.

It definately improves smoothness but remember...the trannies we have are inherently notchy which we just have to live with.