Automaker to Upgrade ATF Specs


(COLORADO SPRINGS, Colo.) Saying that many automatic transmission fluids today are inadequate to meet its service life and performance goals, General Motors this week unveiled a significant upgrade to its Dexron III ATF specification.

The move will force ATF formulators and blenders to undergo a costly round of testing in order to obtain upgraded Dexron III “H” licenses, and will probably force most ATF manufacturers to use Group II and II-plus base oils in their products.

In a presentation Monday to the Independent Lubricant Manufacturers Association, GM staff project engineer Roy Fewkes said the new tests and limits for the upgrade should be implemented by year end, and Dexron III “H” licensing could begin as early as spring 2003. No new “G” licenses will be issued once “H” licensing begins, but current “G” licensees will have a reasonable period — about one year — to convert to the new formulations.

Fewkes stressed that the upgrade, although significant, is not the “step-change” that would require introducing Dexron IV, because some current products, including GM factory-fill ATF, already meet the upgraded spec. But all ATF sold in the service fill market will have to undergo testing to demonstrate compliance with the upgrade.

In looking at current ATF formulations, Fewkes explained, GM saw numerous products it calls “inadequate” for its requirements. Primarily, the difference in these fluids seemed to be driven by base stock selection, not the additive chemistry. Group II-based ATFs generally outperformed those using Group I oils, he noted.

“Now that the formulations of many ATFs have changed to using Group II base oils, we’re seeing that the failure mode for these fluids is not due to oxidation, but because the friction system fails,” Fewkes noted.

He believes that the new specification will drive formulators to use more Group II and II-plus base stocks, while “the Group I stocks will be the ones that disappear from these formulations.

“This change won’t eliminate any basic additive chemistries,” he told the group. “Our approach is primarily formula-driven, not chemistry-driven.”

Reaction from ILMA members focused immediately on the testing costs that the new licenses will create.

Currently, most ATF formulation and testing costs are borne by the additive manufacturers, who qualify a particular additive package in a specific base stock — a so-called “original” formulation. Lube manufacturers then must buy those specific qualified ingredients to make their ATF, and must pay to test their “reblend” of this identical formulation. One lube company owner estimated that a reblend test regimen costs approximately $30,000, and an additive company representative indicated that the “original” test costs can be two to three times that.

GM’s Jim Linden was uncertain what the testing costs are, but said he does not believe the “H” test costs will differ significantly from today.

Tests for the new “H” licenses will include a low-speed friction test; a cycling test to measure shift durability; a plate friction test to run 150 hours instead of the current 100; a band friction test; an extended GM oxidation test to run 50 percent longer (to 450 hours); and a newly developed air entrainment test. A new slate of seal materials will also be used in seal compatibility testing.

Licensing fees for the upgrade will still be $3,000 per year for an active license and $750 for the inactive.

More information about the licensing program is available from Richard Zampardo, who has replaced John Flaherty as GM Dexron licensing program manager. He can be reached by phone at (248) 857-4510 or by email at

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