M7 Manual transmission fluid question

Afterimage said:

For owners of the C7 with M7 what kind of fluid are most of you using when it's time to change out the fluid in your tranny? The GM spec fluid is part #88861801 I take it this is not a synthetic fluid................if you are using a synthetic manual trans fluid in your TR6070 what are you using?

Tony

Click to expand...

For what it is worth - I switched over to Royal Purple Trans Fluid ("Forumulated for manual transmissions using Automatic Transmission Fluid" I recall on the package). It promises smoother shifts, better (not as notchy) cold transmission operation, and good fluid life. Mine is a 2019 Stringray base with the 7-speed.

Results after about 2 years - yes, I do notice much smoother shifting, still a bit notchy during cooler weather but at least a 75% improvement over the regular GM dino oil. I believe, but can't be sure, that the Royal Purple is also dino-oil based, haven't delved into that very much since frankly I've been very happy with the results so far. Car was purchased April 2018, fluid changed after the second summer at about 17,000 K, vehicle now has about 38,000 K after this 6th summer of operation. You can get it at any Royal Purple dealer, or at Canadian Tire believe it or not.

Late Life Crisis
Aurora

Follow up to previous post - the Royal Purple "Synotech" is definitely a synthetic. I remembered I had a bit left in the original bottle on a garage shelf, went to look, confirmed it isn't Dino-oil. Also saw on the Canadian Tire page when I enlarged the image.