Allison fluid

JRZ2500HD · September 21, 2003

i just want to make sure i run the correct fluid. ami correct assuming you use dexron III?

SoMnDMAX · September 22, 2003

You are correct. Dexron III is the spec'd fluid for the Allison.

CMNTMXR81 · September 24, 2003

Dexron III will work fine. However, Allison prefers/recomends their costly synthetic called Transynd. It's made by Castrol.

That's what I use in mine. But like I said it's expensive so, if you want to go the cheap route, a regular Dexron III is sufficient.

awdvkd · September 24, 2003

Transynd is not a pure synthetic, it is a mix. Its expensive but you don't have to change it as often. I like the mobil1 atf, its made mine shift better than the stock stuff. I use Mobi1 from front to back bumper.

bigdogs · September 25, 2003

What is it filled with out of the factory then, Dexron III or Transynd

k1500chevy97 · September 25, 2003

got a a 450hp cummins M11 with an allison automatic behind it . It says 23 quarts of regular ol dextron3

CMNTMXR81 · September 25, 2003

That's because Dexron III (they can't even spell it right) is much more commonly available and commonly used and much cheaper. It works sufficiently for anything you can throw at it. Conversely Transynd is only available (at least around here) at an Allison dealer, is costly and is the extra "insurance" for your needs.

Just like most GM engines nowadays require an SE/SF approved 5W-30. They don't care what brand, as long as it's that weight and viscosity, it'll work. The brand, qaulity, etc, is your decision.

SoMnDMAX · September 25, 2003

What is it filled with out of the factory then, Dexron III or Transynd

Dexron III, as far as I know.

CMNTMXR81, you heard anything different on the factory fill?

CMNTMXR81 · September 25, 2003

GM tries to cut costs wherever possible on the assembly line, hence they wouldn't "pop" for Transynd from the factory. It's Dexron.

bigdogs · September 25, 2003

Thanks I guessed it was the cheaper Dexron but then when I saw Allison recommends the other wasn't sure. I'd like to at some point change over all the oils to synthetic (probably AMSoil), especially since it gets cold here but being the truck (with duramax/allison) is brand new (700 miles) I have a bit of time to go before any of the changes.

I did read somewhere that even GM recommends synthetic axle lube in the front in very cold climates.