Castrol TranSynd 668 Allison 2021 Updated SPEC CASE

Great product good people to do business with had a problem fixed it right away.

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.

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.

I think the best fluid for Allison transmission

Good for 05 lly dmax after both filters and a fluid fill the trans is noticeably quicker shifting

Fast shipping and the three gallons of Transynd arrived in great condition.

Only stuff I use in my Allison

I bought this to swap the transmission and transfer case fluids out from Dexron to Transynd on my 2017 Silverado 2500. The packaging on the first order didn't survive the trip and I had transmission fluid leaking on my patio. I called Amazon and they promptly sent out another shipment.