Selecting the proper automatic transmission fluid (ATF)

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Selecting the proper automatic transmission fluid (ATF) can be a complicated proposition. It isn’t always clear whether a specific ATF is proper for your vehicle. Because using the wrong one can damage the transmission, getting the right one matters. So, a little background information may be helpful.

Automatic transmission fluids have specific viscosities, friction coefficients, and additives. ATFs are engineered to work with the design of specific automatic transmissions. They are not all the same. Moreover, if your vehicle is still under warranty, using a fluid thatis not approved by the vehicle manufacturer will void the transmission warranty.

Automobile companies develop automatic transmission fluids, or at least set specifications for them. But the car companies don’t make ATF. Petroleum companies handle that. They manufacture ATF according to a recipe of base oils and additives set by the car company and licensed to the oil company. The license fee also allows the oil company to use the automaker’s proprietary ATF brand name. The most common names are Dexron, Mercon, and ATF+4, which are brand names of General Motors, Ford, and Chrysler fluids, respectively.

But, auto manufacturers usually cease licensing old ATF formulations after they’ve introduced a new ATF. In the last several years, all of the major automakers have introduced fully synthetic ATFs, superseding conventionally based ATFs previously used. Vehicles that were originally delivered with the old ATF formulation generally can use the new ATF instead. Or, the old ATF can be replaced with a fluid that an oil company says meets the standards originally set by the car maker for the old formula ATF.

When oil companies make old formula ATFs, though, they try to streamline. Rather than use the precise formula originally set by the car manufacturer, the petroleum companies try to make one fluid that meets several different manufacturers’ original specifications. These are “multi-vehicle” ATFs. A typical example is a fluid that says it meets the specifications of both Dexron III and Mercon V.

Unfortunately, as a customer, it is very difficult to assess whether a particular multi-vehicle ATF is, in fact, suitable for a specific vehicle. With a currently licensed fluid, you know the fluid will work properly because it is manufactured to the precise standards of the auto company. But multi-vehicle ATFs are manufactured to whatever standards the petroleum company chooses, and representations about the ATF’s quality and applications are based on their own testing, not that of the vehicle manufacturer. Moreover, some of the advertising just isn’t accurate.

Over the years, the various formulations of Dexron and Mercon were adopted by a number of other auto manufacturers as the specification for their automatic transmissions, as well. Moreover, because Dexron and Mercon were very similar, these fluids themselves came to be regarded as interchangeable. But, this has led to a nasty habit among some oil companies of claiming that their Dexron/Mercon specification ATF can be used in a whole list of vehicles made by manufacturers other than General Motors and Ford, often for no better reason that once upon a time some model made by that company used Dexron/Mercon.

For example, Valvoline claims in its promotional materials that its DEX-MERC MaxLife ATF is "recommended for use in GM, Ford, Mazda, Toyota, Chrysler, and most import vehicles." Notice they omitted the word "all." If you put MaxLife into a vehicle that is supposed to be using Dexron VI or Mercon LV, you have voided the warranty on the transmission. Moreover, this Valvoline ATF is essentially a version of the old Dexron III and Mercon ATFs. Since 1998, Chrysler has been using a synthetic ATF, either ATF+4 or ATF+5, which Chrysler specifically says is not compatible with either Dexron or Mercon. Valvoline’s ads claim this fluid is “recommended” for Chrysler products. However, Valvoline’s own “product data sheet” (the data sheet produced for every motor oil and ATF giving its specifications, which can be found on the petroleum company’s website) says that this ATF is recommended for GM vehicles, (which use Dexron III), and Ford products (using Mercon) and does not claim this fluid is recommended for any Chrysler product, much less GM products using Dexron VI or Fords requiring Mercon LV.

Other petroleum companies also make overbroad claims for their multi-vehicle ATFs. Quaker State says their Multi-Vehicle ATF is "recommended" for Chrysler, Honda/Acura, Toyota, Nissan, VW/Audi, BMW, Hyundai, Mitsubishi, Mercedes-Benz, Saturn, and Jeep vehicles and "suitable" for many more, including GM vehicles and Ford vehicles. But the product data sheet for that ATF makes no mention of BMW, Volkswagen, Audi, or Mercedes-Benz, or Saturn. Instead, the product data sheet lists primarily applications that use either Dexron III or Mercon V. Most BMW, Mercedes-Benz, Volkswagen and Audi vehicles don’t use Dexron/Mercon type fluids. Believing the advertising could be a very expensive mistake.

Even product data sheets can provide questionable information. Fina’s product data sheet for its "Dexron-III/Mercon ATF" says it is recommended for "all late model GM...Chrysler and most imported car...automatic transmissions, as well as, (sic) those in Ford vehicles that call for a Mercon fluid." But, again, a fluid compatible with Dexron III or Mercon is not going to be compatible with Chrysler ATF+4 or ATF+5, nor will it be proper for either Dexron VI or Ford LV vehicles. The product data sheet is simply wrong.

Whenever a multi-vehicle ATF is advertised as suitable for a long list of vehicles, be suspicious. Most of these fluids are simply versions of Dexron III or Mercon. Unless your car was delivered new with Dexron III (or an earlier version of it), Mercon, or Mercon V fluid, you should be sure to check the product data sheet of any multi-vehicle ATF before using it. If you have any doubt that Dexron III or Mercon is suitable for your car, do not take the risk of using a multi-vehicle fluid.

There are a couple of other complications, too. Your GM car might take Toyota transmission fluid, or Honda transmission fluid. Your BMW might take the same ATF as your neighbor’s Audi. Heck, your new BMW might actually use Dexron VI. The Pontiac Vibe is actually equipped with a Toyota transmission, and the Saturn Vue has several models with Honda transmissions. BMW buys its newest automatic from General Motors. Audi, BMW, Jaguar, and Volkswagen all buy transmissions from ZF, a German transmission company.

So, to select the proper ATF for your car, start with the owner’s manual. The manual will state the recommended ATF, as of the time the car was new. With that starting point, here’s a list of transmission fluids that either are, or have been, on the market and what superseded what:

Type A and Type A, Suffix A—very old transmission fluids superseded by Dexron and Mercon. Equivalent to Mercedes-Benz Sheet 232.2.

Dexron, Dexron II, IID, and Dexron IIE—these are the original GM Dexron ATFs and are no longer licensed by the company, having been superseded by Dexron III, which has now itself been superseded by Dexron VI. The difference between Dexron, II, and IIE was mostly in the oxidation inhibitors.

Dexron III and IIIH—OE ATF at GM for many years and widely adopted by other manufacturers. General Motors nowconsiders all of them to be obsolete and discontinued licensing Dexron IIIH in 2006. Dexron IV was an upgraded version of Dexron III, which was used by GM only briefly.

Dexron III/Saturn—a version of Dexron III developed for certain Saturn models.

Dexron VI—the newest GM ATF, it was developed specifically for the new six-speed automatic and is a synthetic blend (meaning it has some conventional base stocks). That transmission has tighter internal tolerances and required a fluid that had higher shear strength that Dexron III.

It was introduced with the 2006 models. GM considers Dexron VI to be "backward compatible," meaning GM recommends it for use in any vehicle that originally used any earlier version of Dexron and that it can be mixed with them. However, GM specifically recommends against using Dexron VI in non-GM made vehicles that used Dexron III as original equipment. It is also the specified ATF in certain non-GM models that use GM transmissions, such as BMW. It is not, however, specified for GM brand vehicles that have non-GM transmissions, as mentioned above, or are imported to the United States.

NOTE: Dexron VI is not recommended for: Pontiac Vibe and Wave, Chevy Aveo, Epica, and Equinox, Saturn ION with CVT or AF23 transmission, Saturn Vue with CVT, AF33 or 5AT transmissions, or 1991–2002 Saturn S. These are vehicles with transmissions that were not manufactured by General Motors.

Ford Type F—an old ATF first introduced in 1967 and used in all Ford products prior to 1977, and in some until 1980; also used in various import vehicles of the period, including Mercury Capri, Jaguar, Mazda, Saab, Toyota, and Volvo. Type F is not compatible with any other ATF. Specifically, it is not compatible with Mercon ATFs.

Ford Type H—developed for the C5 Ford automatic transmission introduced in 1981, it has been superseded by Mercon. Type H is not compatible with Type F and should not be used in a transmission requiring Type F.

Ford Type CJ—originally designed for the Ford C6 automatic transmission, it also has been superseded by Mercon and also can be replaced with Mercon V, but should never be used in a transmission requiring Type F. Dexron II is an approved alternative to Type CJ.

Mercon—introduced in 1987 and similar to Dexron II. Ford ceased licensing Mercon in 2007 and now recommends Mercon V for all transmissions that previously used Mercon. Mercon is a suitable replacement for Type H and Type CJ fluid, but not for Type F.

Mercon V—the most common Ford ATF in late model Fords, it is very much like Dexron III. Should not be used in a transmission requiring Ford Type F.

Mercon LV—the latest Ford ATF, it is factory fill in 2008 and later Fords. The LV stands for "low viscosity." It is a fully synthetic ATF. It is not compatible with earlier Mercon fluids, so it should neither be mixed with Mercon or Mercon V used to replace those fluids. It is not compatible with any other fluid, either.

Mercon SP—a version of Mercon V with an enhanced additive package.

Mercon CVT—Ford ATF specifically developed it for models with continuously variable transmissions.

Chrysler 7176—now obsolete Chrysler fluid for front wheel drive vehicles.

Chrysler ATF+2, also called 7176 D—first used in 1997, added oxidation protection and better cold weather flow than 7176.

Chrysler ATF+3, also called 7176E—designed for four-speed automatics, uses better quality base oils to obtain higher strength than ATF+2. Should always be used in 1999 and earlier Chrysler manufactured minivans, rather than later versions of Chrysler ATFs.

Chrysler ATF+4, also called ATE—a synthetic ATF introduced in 1998, it should always be used in any vehicle in which ATF+4 is specified. It can be used in Chrysler vehicles manufactured in prior years, except for minivans from before 2000, which use the 41TE/AE transmission. It is not compatible with Dexron or Mercon fluids.

Chrysler ATF+5—synthetic ATF used in 2002 and newer models, it is not compatible with Dexron or Mercon fluids.