Stone River Products Castrol TranSynd 668 Allison 2021 Updated SPEC 1 GALLON ONLY BY DOXA WORLDWIDE

TranSynd 668 is one of the best transmission fluids available on the market currently. Developed specifically to meet rigorous Allison specifications for heavy-duty working trucks. Also works in GM transmissions like 4L80 and 6L90 and has better performance than standard ACDelco or GM Dexron VI or III fluids. OK to mix with Dex until the next fluid change. TranSynd is considered a more versatile premium synthetic option that meets a wider range of specifications and has a higher shear resistance. It can withstand more shearing forces without breaking down, making it a better choice for applications requiring extreme durability. Been running it in all of my GM and Allison transmissions for many years. Recommended.

This is the only transmission fluid I will use on my truck period !!

Great fluid. Chevy shifting so much better now.

Case of three 1 gallon containers arrived with no spills or issues mentioned in other reviews. Did an Allison 1000 transmission fluid and filter (x2) change on my 2017 Chevy Silverado 2500HD Duramax. I also changed out my transmission cooler lines at the same time to upgrade my cooling system. The allison 1000 change usually takes about 10 quarts of fluid. With the additional line replacements, I need a couple extra quarts to re-fill so this package worked perfect. Was able to put all three jugs in and it put the level right where it needs to be. Also saved a few bucks ordering it through Amazon versus my local auto parts stores.

TranSynd 668 is perfect for your Allison Transmission

Did a 50,000 mile change in my 2018 Chevy 3500. After change shifts felt smoother and picked up around 1 MPG on next three tanks of fuel.

good price for the gallon

Shipped and delivered quickly. Bought this for my 03 Duramax with the Allison 1000 5-speed. I heard this was the best fluid for an Allison. As of right now and the past few thousand miles it has been perfect. Time will be the true tester.