synchromesh friction modified

[RIC0900]

Hi all,
I have an'07 Taco, just broken in, and I want to drain my manual transmission fluid. I'm wondering if I could use this GM synchromesh trans fluid. I hear that it will make transmission shifting smoother. My owner's manual states oil type: Gear oil API GL-4 or GL-5. Viscosity: SAE 75W-90. Is the GM synchromesh modified GL-4 or GL-5 compatible? I did some research, but it didn't help much. Any thoughts from the wise guys?

Thanks.

 

[INDYMAC]

The GMSMFM is a lighter weight manual transmission fluid than 75W90 GL 4/5. If that is what your owners manual calls for in your transmission, then I would use a 75W90 gear oil. M1, RL, Amsoil and others make good ones. Are you experiencing any shifting difficulties?

 

[Pablo]

I'm not sure of the exact viscosity of GM Syncromesh, but I do believe it's way too thin for a tranny requiring 75W-90.

If you are having trouble in cold you may want to go with a synthetic MT fluid such as:

Amsoil MTG 75W-90 GL-4

 

[unDummy]

Stick with the required weight gear oil.
If you need a GL4 90wt gear oil, plenty threads are here recommending various brands.
http://theoildrop.server101.com/forums/showflat.php?Cat=0&Board=UBB16&Number=783860

 

[MolaKule]

The GM Synchromesh is approx. 9.3 cSt in viscosity, or a high 20 weight, low 30 weight, and is way to thin for a transmission requiring a 75W90.

If you live in St. Louis latitudes or above and use Amsoil fluids , I recommend 1/3 AMSOIL MTF and 2/3 MTG.

 

[Trex101]

Redline High Temp ATF is rated GL-4 with 10cSt@100'c. I would say it's pretty close to OEM GM spec.

 

[KBFXDLI]

Go on the Redline website and put in an application request. They will have a fluid for you that is most likely cheaper than the GM lubricant.