Automatic Transmission Fluid (ATF) Guide

► How to Check Automatic Transmission Fluid Condition

► How to Properly Check Transmission Fluid Level

► DIY Fluid and Filter Change

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Automatic 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 at the bottom of this page 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.

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

At approximately 255 to 260°F, 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 295°F, 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 315°F), 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.

Transmission and Transaxle
Heat Temperature Failure Chart

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 at the bottom of this page.

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)

Fluid Color: Red Transparent
New or Like New Condition

Continue checking fluid condition regularly and follow the manufacturer’s recommended transmission service procedures and schedule.

Fluid Color: Light Brown – Semi Transparent
Good Condition


Continue checking fluid condition regularly and follow the manufacturer’s recommended transmission service procedures and schedule.

Fluid Color: Dark Brown – Opaque
Old/Dirty Fluid
Does not provide adequate lubrication – will cause transmission to run hot.  Recommend flush or fluid and filter change.

Fluid Color: Very Dark/Black
Old/Dirty and Oxidized
Fluid has a burnt odor.  Some internal transmission damage has occurred.  Fluid and filter change may prolong transmission life.  A flush is not recommended.

Fluid Color: Light Pinkish
Water/Coolant Contamination
Internal transmission damage has occurred.  A fluid flush may prolong transmission life.  Repair transmission oil cooler/cooler line leak.

Street Smart® Technical and DIY Guides

Reflashing and ReprogrammingWhat is reflashing / reprogramming? What are your options when your vehicle needs reflashed after a new transmission is installed. Typically for 2005- Ford and GM 6-speed, 8-speed, 9-speed and 10-speed vehicles.
Automatic Transmission Repair CostsWhat is a fair price to pay for various transmission repairs? What kinds of repairs does a transmission need?
Automatic Transmission Rebuild CostsDoes your transmission need rebuilt? Fair price guide for the price range of a transmission rebuild.
Remanufactured Transmission Options and CostsConsidering a remanufactured transmission? Here are costs and options for how to purchase.
Get a Free Transmission Estimate by EmailWant an estimate for a remanufactured transmission? Fill out the form here to get an estimate via e-mail.
How to Replace a Transmission Torque Converter Clutch SolenoidWhat is a transmission torque converter clutch solenoid and how to replace one if it goes bad.
How to Replace a Transmission Pressure Control SolenoidWhat is a transmission pressure control solenoid and how to replace one if it goes bad.
How to Replace Transmission SolenoidsGuide to various automatic transmission solenoids, how they work, and DIY instructions.
How to Remove and Install an Automatic Transmission - (RWD)If you are facing a transmission replacement, you can reduce the cost considerably by removing and re-installing the transmission yourself. Here we provide step-by-step instructions for removing and replacing a transmission.
How to Replace a Transmission Speed SensorFor most vehicles, the speed sensor is plugged into the transmission (or transaxle). When the speed sensor fails the speedometer stops working and shifts may become erratic. Replacing a speed sensor is easy.
How to Release a Shifter Lever That is Stuck in ParkNothing is more frustrating than getting into your car and the gear shifter lever being locked in Park. Here we explain how to release the shifter, the causes, how to repair and the estimated cost.
How to Install an Automatic Transmission Oil CoolerInstalling an auxiliary transmission oil cooler can protect your transmission from overheating and failure. Excessive heat can ruin a perfectly good transmission very quickly. Coolers are inexpensive and easy to install.
How to Check the Condition / Level of your Automatic Transmission Fluid and Change Fluid / FilterLearn how to check the condition of transmission fluid, what the different conditions mean and what, if anything, you need to do to keep your transmission running smooth. Learn the correct procedure for checking transmission fluid level. Many people do it wrong, so here is the easy way. Keeping clean fresh fluid in your transmission is the number one thing you can do to protect the transmission from premature failure. These DIY transmission fluid and filter change procedures are easy to follow.
How to Replace a Transmission Neutral Safety SwitchThe neutral safety switch is a safety feature that prevents the engine from starting when the transmission or transaxle is in gear. When the switch fails, the engine may not crank or it may start in gear.
How to Flush Your Automatic TransmissionA transmission fluid flush can be performed without a transmission flush machine - and it's safer for high mileage vehicles.
What is Limp Mode?When a transmission fault is detected by the OBD-II system, the transmission may go into fail-safe (or "limp" mode as it is also called) in order to protect the transmission from internal damage
Transmission Diagnostic Trouble CodesDiagnostic Trouble Codes P0700 through P0799 are transmission related OBD-II codes. Any code within this range point to a transmission related fault..
How to Inspect and Repair CV Axles and CV JointsCV (constant-velocity) axles, (also known as half-shafts), are used in front-wheel drive vehicles to transfer the engine’s power from the transaxle to the two drive wheels.
Auto Repair SafetyWhen working on or around any vehicle injuries can and do occur. Please read these Safety Precautions before starting your next automotive service/repair project.