Rick's Free Auto Repair Advice

Transmission Fluid — What is transmission fluid?

What is transmission fluid?

Transmission fluid is a lubricant that prevents wear on transmission parts. But it serves a second purpose, and that it to apply pressure to servos and clutch pack pistons to force clutch discs and bands to apply. To help with clutch and band application, car makers specify different friction modifying additives for their fluids.

What makes transmission fluid different from motor oil?

Transmission fluid has many of the same additives as motor oil like: anti-wear additives, rust and corrosion inhibitors, detergents, dispersants and surfactants. In addition, transmission fluid contains viscosity index improvers and modifiers, seal swell additives, anti-foam additives and anti-oxidation, cold-flow improvers, high-temperature thickeners, gasket conditioners, pour point depressant and dye.

What are the different types of transmission fluid?

Each car maker has their own recommended transmission fluid based on the individual transmission. Even though oil companies sell “universal” transmission fluids and transmission fluids that work in “all makes and models,” not a single car maker recognizes these universal fluids. In fact, if you compare the car maker’s fluid specifications to the specifications on the universal fluids, there is NO WAY a single universal fluid can possibly meet all car makers transmission fluid specifications. Some of the specifications are even mutually exclusive.

• ATF+4 The current transmission fluid for Chrysler products. Replaces ATF+3, ATF+2, ATF+

• DEXRON VI The most current transmission fluid for GM vehicles. It is backwards compatible with Dexron III/Mercon

• Mercon V The most current transmission fluid for most Ford, Mercury, Lincoln, and some Mazda vehicles

• Mercon LV The recommended transmission fluid for some Ford(DuratecHE) and Mazda vehicles

• Mercon SP – For the Ford 6R transmission

• Toyota ATF Type T-IV (T4) The fluid for some Toyota and Lexus vehicles. Replaces Type T, Type T-II and Type T-III.

• Toyota ATF WS The fluid for some Toyota and Lexus vehicles with CVT transmission.

• DW-1 The fluid for Honda and Acura (except CVT). Replaces Z1 specification fluid

• Diamond SP-III (or SP3) The fluid for Mitsubishi (including CVT’s), Hyundai and Kia 4-speed automatic transmission.

• Diamond SP-IV (or SP4) The fluid for Hyundai and Kia 6-speed automatic transmission.

• Nissan Matic The fluid for Nissan and Infiniti vehicles

Matic D is for 3- and 4-speed transmissions,

Matic K is for 5-speed front-wheel-drive transmissions,

Matic J is for 5-speed rear-wheel-drive transmissions,

Matic-S fluid supersedes Matic-J fluid.

• ATF-HP The fluid for some Subaru vehicles, except CVT transmissions. 2004 and earlier Subaru vehicles use Dexron III.

• Mazda M5 (MV) The fluid for the Mazda FN4A-EL/Ford 4F27E and Mazda FS5A-EL/Ford FNR5. Also sold as Ford FNR5 fluid. Genuine Mazda M5 is made by Idemitsu Corporation, available as Idemitsu Type-M.

• Mazda FZ fluid The fluid for the SKYACTIV-Drive. Color of this fluid is blue.

Can you use a universal or all makes and models transmission fluid?

NO! NEVER use a universal or all makes and models fluid in your transmission.


Can you mix transmission fluid types?


What causes transmission fluid to fail?

High heat caused by getting stuck and rocking the vehicle back and forth between drive and reverse. Neglecting recommended transmission fluid changes.

When to get a transmission fluid flush?

Most car makers do NOT recommend transmission fluid flushes! At best they recommend a drain and refill. In fact, many car makers have issued service bulletins warning their dealers NOT to recommend a transmission fluid flush as a routine service.

Follow the car makers’ maintenance manual for transmission fluid change intervals. Insist the shop uses the recommended fluid for the fluid change or flush.

Read this post on transmission fluid flushes

©, 2018 Rick Muscoplat

Posted on by Rick Muscoplat


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