CAMARO6 - View Single Post - M6 trans fluid viscosity inconsistencies: OEM vs Dexron III ATFs

N Camarolina · 01-22-2021, 08:19 PM

I've been researching M6 trans fluids threads for a while now in search of potential alternatives to the OEM fluid in my new SS 1LE, mostly because I don't like the cold shifting and nibbling characteristics. I was hoping to find a better cold functioning fluid that could still protect adequately on the track. Along the way, I took note of the point that has been raised by others about the need to look at product data sheets, specifically the viscosity ratings at 40 and 100 c temps. I'm not claiming to be the one genius among us, but I think I just uncovered some stats that have me second guessing the use of ATF in the M6, or if not that, why GM has selected the fluid they have when Tremec says to use Dexron III ATF. Allow me to explain......

Tremec says in the TR6060 data sheet to use Dexron III ATF. Many users have followed this guidance and use their favorite brands (RP, RL, Amsoil, M1, etc). All of those fluids are (I think) full synthetics and pretty much have similar viscosity ratings that are about 36 at 40c and 7.5 at 100c. Redline D4 even has a video on their website where they mention that the Tremec and BMW manual trans have tighter tollerances and therefore need a lower viscosity lubricant such as ATF rather than typical manual trans lubricant.

HOWEVER: The OEM fluid in our M6 appears to have significantly higher viscosity (15 at 40c and 75 at 100c) and is mineral oil, not synthetic. The relatively new Tremec trans fluid is very similar to the OEM in this regard.

This raises two important questions in my mind?

1) If Tremec reccommends a Dexron III ATF in the TR6060, why is the OEM fluid and Tremec's new fluid twice as viscous as the Dexron III ATF fluids most forum members are using (RP, RL, Amsoil, etc)? Is the OEM and Tremec fluid thicker than it should be for the trans design, or are the ATF fluids actually too thin?

2) If we use ATF Dexron III (RP, RL, etc) with the thinner viscosity at the track, are we putting more wear and tare on our trans than if we had stuck with OEM or Tremec's fluid?

Curious to hear others thoughts with respect to the viscosity issues and these two questions. Please don't hijack the thread and tell everyone about your favorite M6 fluid. I'd like to keep it focused on the two questions I've raised.

01-22-2021, 08:19 PM	#1
N Camarolina Drives: 2021 2SS 1LE Join Date: Aug 2020 Location: Cary, NC Posts: 802	M6 trans fluid viscosity inconsistencies: OEM vs Dexron III ATFs I've been researching M6 trans fluids threads for a while now in search of potential alternatives to the OEM fluid in my new SS 1LE, mostly because I don't like the cold shifting and nibbling characteristics. I was hoping to find a better cold functioning fluid that could still protect adequately on the track. Along the way, I took note of the point that has been raised by others about the need to look at product data sheets, specifically the viscosity ratings at 40 and 100 c temps. I'm not claiming to be the one genius among us, but I think I just uncovered some stats that have me second guessing the use of ATF in the M6, or if not that, why GM has selected the fluid they have when Tremec says to use Dexron III ATF. Allow me to explain...... Tremec says in the TR6060 data sheet to use Dexron III ATF. Many users have followed this guidance and use their favorite brands (RP, RL, Amsoil, M1, etc). All of those fluids are (I think) full synthetics and pretty much have similar viscosity ratings that are about 36 at 40c and 7.5 at 100c. Redline D4 even has a video on their website where they mention that the Tremec and BMW manual trans have tighter tollerances and therefore need a lower viscosity lubricant such as ATF rather than typical manual trans lubricant. HOWEVER: The OEM fluid in our M6 appears to have significantly higher viscosity (15 at 40c and 75 at 100c) and is mineral oil, not synthetic. The relatively new Tremec trans fluid is very similar to the OEM in this regard. This raises two important questions in my mind? 1) If Tremec reccommends a Dexron III ATF in the TR6060, why is the OEM fluid and Tremec's new fluid twice as viscous as the Dexron III ATF fluids most forum members are using (RP, RL, Amsoil, etc)? Is the OEM and Tremec fluid thicker than it should be for the trans design, or are the ATF fluids actually too thin? 2) If we use ATF Dexron III (RP, RL, etc) with the thinner viscosity at the track, are we putting more wear and tare on our trans than if we had stuck with OEM or Tremec's fluid? Curious to hear others thoughts with respect to the viscosity issues and these two questions. Please don't hijack the thread and tell everyone about your favorite M6 fluid. I'd like to keep it focused on the two questions I've raised.