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Automatic Transmission Fluid (ATF)

 
 

Automatic Transmission Fluid - The Lifeblood of an Automatic Transmission

 
automatic transmission fluidAutomatic transmission fluid is a specially formulated oil designed to meet the requirements of automatic transmissions and the rather harsh conditions under which they must perform.  The fluid is typically red in color and translucent.  The red color of ATF distinguishes it from other fluids used in your vehicle, which helps reduce the risk of adding a different fluid, such as engine oil, to the transmission.  The red dye in automatic transmission fluid also helps distinguish it from other fluids when a leak occurs.  automatic transmission fluids

All automatic transmission fluids contain a number of different chemical compounds designed to lubricate, cool and clean the internal parts of the transmission.  Other compounds that make up automatic transmission fluid include rust and corrosion inhibitors, detergents, anti-foam additives, anti-oxidation compounds.

But, while most automatic transmission fluids contain each of the above mentioned compounds and additives, they are not the same.  Each type of ATF is developed for a specific list of automatic transmissions and transaxles - they each have a specific viscosity and a specific friction coefficient that is best suited for the transmission they are designed for.  See the Condensed Automatic Transmission Fluid Application Chart below or our full Transmission Fluid Application Guide for the correct fluid to use in your vehicle.

Inside the Transmission

Inside the transmission, in addition to providing lubrication to all the moving parts and gears, ATF also provides hydraulic pressure to the transmission's clutches and bands to engage and shift gears.  To keep the fluid and transmission from overheating, a transmission oil cooler located inside the vehicle's radiator continuously cools the transmission fluid when the vehicle is in operation.

When Transmission Fluid Overheats

Even with its built-in cooling properties and external oil cooler, transmission fluid can and does overheat more often than most vehicle owners realize.  Common causes for transmission overheating include:

  > Low fluid level, old, dirty and/or oxidized fluid
> Clogged or restricted transmission filter
> Engine Overheating
> Transmission slipping,
> A failing torque converter or faulty torque converter clutch solenoid
> Extended stop and go traffic, extended travel through desert or mountains
> Towing
> Spinning the wheels
> Racing

The Consequences of Excessive Transmission Heat and Fluid Oxidation

Under normal operating conditions and when operated within its designed temperature range (between 175 and 195 degrees Fahrenheit for most vehicles) a good quality transmission fluid will provide in the neighborhood of 100,000 miles of service before oxidation occurs.  But, as you can see in the chart below, when the temperature of ATF rises, things begin to deteriorate very rapidly.

Transmission
Fluid
Temperature
Approximate
Fluid Life
Expectancy
175 to 195 F
215 F
235 F
255 F
275 F
295 F
315 F
335 F
355 F
375 F
395 F
100,000 miles
50,000
miles
25,000
miles
12,500 miles
  6,250
miles
  3,125
miles
 
1,600 miles
    
800 miles
    
400 miles
    
200 miles
    
100 miles
 
 
A brief narrative explaining the Transmission
Fluid Temperature/Failure Chart.

At approximately 235F, vital transmission fluid additives start to boil.  This results in varnish build up inside the transmission.

At approximately 255 to 260F, the internal seals begin to harden, which causes both internal and external fluid leaks.  Internal leaks equates to pressure loss, which causes slipping and a variety of shift problems.

When the fluid temperature reaches 295F, the fluid continues top breakdown at a rapid pace.  At this point the fluid no longer provides adequate lubrication and the clutch plates burn up and slip badly.

At the next 20 temperature increase, (approximately 315F), the seals and clutches are completely fried and the transmission is doomed.  Catastrophic transmission failure is eminent and will occur very soon if it has not already failed.

All Automatic Transmission Fluids are Not the Same

Automatic transmission fluid is designed to work with a specific list of transmissions.  Using the wrong type of ATF in your automatic transmission can adversely affect the performance of the transmission and, in some cases, actually damage the transmission.  Moreover, adding the wrong type of transmission fluid will void the vehicle manufacturer's warranty.  So, as long as your warranty is in effect, you'll want to follow the manufacturer's guidelines exactly when adding fluid or when servicing the transmission.  Check your Owners Manual for the type of transmission fluid for your vehicle. 

Note:
If you do not have the vehicle Owner's Manual, the transmission fluid type for your vehicle may be indicated on the transmission dipstick. Alternatively, check the ATF Application Guide below or see our full Transmission Fluid Application Guide here.

ATF+4: Most Dodge, Jeep, and Chrysler vehicles

Mercon V: Most Ford, Mercury and Lincoln vehicles

Mercon LV: Some Ford and MAZDA vehicles

DEXRON: Most GM and pre-2004 Toyota Vehicles and some Ford vehicles

ATF DW-1: All Honda and Acura (not CVT transmissions)

SP-III: All Hyundai, Mitsubishi and Kia vehicles (not for CVT and dual clutch transmissions)

Matic S, Matic K, Matic D: Nissan and Subaru vehicles

Toyota ATF-WS: All 2004 and newer Toyota vehicles

Honda DW ( ZF ): All Honda vehicles (not for CVT)
 

 
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