Thirteen fluids are approved under TES 295, including brands from Castrol, BP, BASF, International Truck, Mobil Delvac, Mack, Shell, CNH, Phillips 66, Kendall, Total, Renault Trucks and Transtar Industries, according to Allison’s website.

Service fill opportunities for TES 668 fluids will be similar to those of 295 fluids, Gregory told Lube Report. Service fill volumes range from 10.6 quarts up to 48 quarts in the specified transmissions, and 668 fluids are backwards compatible with any transmission requiring TES 295.

“TES 668 is a modern formulation with many advantages compared to mineral-based, non-synthetic fluids,” the company said in a press release. The new fluid offers enhanced performance over legacy TES 295 fluids in oxidative stability, antiwear performance and friction modifier durability.

“These factors improve the quality of the shifts and reduce the noise, vibration and harshness experienced as the fluid ages. Better friction performance provides more consistent clutch application – even across temperature variations and load sizes,” the release stated.

Along with Voith and ZF, Allison is one of the three major producers of heavy-duty automatic transmissions, each with roughly a third of the global market, according to Jack Zakarian of Jaztech consulting in Orinda, California. However, Allison has the broad majority of market share in North America.

Each OEM has its own extended warranty ATF specification. Synthetic base oils are very common for ATF formulations and are the only oils used for extended warranty fluids, Zakarian continued. However, he speculated that Allison has moved from an all-polyalphaolefin based formulation to one that includes API Group III base oils. Petro-Canada is the only major North American producer of Group III.