Arch: The concern is not that Dexron III is no good, it is that some versions of DexIII on the market MAY not meet the specs of the original DexronIII. A long discussion here;
Dexron IIILook at post #21 for info on the Chevron MD3.
Allison has an improved transmission fluid and recommends/requires Transynd or an equivalent. The Dexron III formula fluid is still acceptable but Allison states the only way to be certain it meets all the specs of what was the DexIII is to submit the formula to Allison to be listed as an approved TES 389. (They actually require that you provide your prior approval as DexIII as part of the application)
Anyway, there are few TES389 applications or approvals as the only issue for using DexIII is it's use in early Allison tranny's. A limited and fading market.
A for instance- suppose Hijack oil company puts out Dexron VI ATF and decides that since it also exceeds all the specs for DexIII and labels it as "DexIII suitable" for all transmissions requiring DexIII. Some early, prior to 2003?, Allisons cannot use Dex VI because it dissolves the seals. (Allisons are the only ones Dex VI affects)
I satisfied my concern by calling Tech support at Mobil concerning my use of Mobil-1 ATF. You could check with Chevron.. We are both out of warranty. (My next fluid change in 2 years will be with Transynd, I have finally used my stockpile of Mobil-1 Synthetic ATF.)
Hooligan U.S. Coast Guard Ret.
2016 THOR Siesta Sprinter 24ST Diesel
2008 SUZUKI Grand Vitara TOAD
1 Pug "Lily", 1 Newfoundland, "George"
1972 MotoGuzzi Eldorado
