More than 90% of the new cars sold in America today have automatic transmissions, but for such a widely-adopted piece of technology, the inner workings of an automatic are a complete mystery to almost everyone who drives. Even hardcore car enthusiasts and racers, people who will confidently rebuild an engine from the crank up or jet a carburetor between rounds, will often feel dread and confusion when considering the eldritch mysteries of the automatic transmission.
Synthetic ATF provides better thermal and oxidative stability over conventional ATF, as well as better cold temperature properties. – Mark Negast, Lucas Oil
While the details of an automatic can be daunting to ponder, there are a few simple things that anyone can do to keep their transmission healthy. Heat is the enemy, whether you race, tow, or commute, because it can quickly break down the properties of the transmission fluid that’s the lifeblood of the transmission, and once the ATF is cooked, expensive repairs are soon to follow.
Using the right fluid is cheap insurance against a costly transmission failure, and Lucas Oil’s Sure-Shift Semi-Synthetic ATF is a Dexron III/Mercon/Mercon V/Allison C-4 compatible formula designed to provide protection and performance without breaking the budget. Lucas Oil Products Technical Director Mark Negast explains, “Typically, synthetic ATF provides better thermal and oxidative stability over conventional ATF, as well as better cold temperature properties. It helps extend the life of the fluid and the life of the equipment.”
For drag racers, launching the car by bringing the engine up to the torque converter’s stall speed while holding the car in place with the brakes or a transbrake can cause ATF temperatures to soar by as much as 100 degrees F per second. That’s brutal punishment that can break down the fluid and cause a transmission to fail. In the same way, a tow rig pulling a trailer up a long grade can put an enormous thermal load on the transmission, adding more heat than even the biggest add-on transmission cooler can pull out. In any circumstance when transmission heat is the issue, a high quality ATF is a necessity to prevent gearbox failure.
So what, exactly is a “semi-synthetic” ATF? “Semi-synthetic means that it has a synthetic base oil component present in the formula,” says Negast. “The concentration varies, but typically most synthetic ATF formulas contain about a 20% synthetic component. Full synthetic ATF formulas contain 100% synthetic base fluids, and are much more expensive. You can use the semi-synthetic ATF for most applications unless the OEM specifically calls out for a full synthetic.” The synthetic component can be scientifically engineered for the specific properties desired, whether that’s heat resistance, a friction modifier, or both, rather than relying on refining those qualities into a naturally-derived base stock.
Here in our own shop, we’re utilizing Sure-Shift in “Sucker Punch,” our shoebox Chevy, soon to be motivated by a small-block topped with Edelbrock’s Enforcer supercharger. With dragstrip grudge nights and extended cruising as part of that project’s mission statement, we need to make sure the transmission is properly protected against heat and wear.
In our case, the Sure-Shift ATF is going into a fresh transmission and torque converter, but per Negast, there aren’t any compatibility issues when switching to Sure-Shift into a transmission that isn’t bone dry. “If the fluid being used meets all of the same specifications as the previous fluid, then there is no need to flush or clean out the system,” he adds.