Choose the Right Automatic Transmission Fluid for Your Transmission
Automatic transmissions use a special type of oil called Automatic Transmission Fluid, or ATF. This fluid has a number of duties in the transmission, including lubrication, cooling and clutch application.
ATF even provides the connection between the engine and transmission through a hydraulic coupling called a torque converter. And, when squeezed between the clutches, ATF acts as a “glue,” providing additional friction and holding capacity to drive the vehicle.
So ATF is a very versatile fluid. That’s why maintaining that fluid can be critical to transmission life.
Several years ago there were only two types of fluid on the market: Type A and Type F. Conventional wisdom said that Type F was for Fords and Type A was for everything else. Conventional wisdom wasn’t all that accurate even back then, and today it’s completely out the window.
Types of fluid
These days there are four main types of fluid on the market. And there are dozens of brands and styles to choose from.
So how do you know what your transmission uses? The easiest way to make sure you’re using the right type of ATF is to check the owner’s manual. It’ll tell you exactly which ATF the manufacturer recommends for your car. You may also find a recommendation on the dipstick. Either is a reasonable resource for determining the right type of fluid for your transmission.
Fluid Types
Here’s a list of the different types of fluids and the basic differences between them:
1. Type F — Yes, it’s still around, as a quick walk through your local parts store will attest. But almost nothing uses it anymore. Type F was designed for Fords that used bronze clutches; the last trans made with bronze clutches was the Cruiseomatic, which hasn’t been used since the early ‘70s. Unless your car is an antique, it won’t use Type F.
2. Dexron III/Mercon — This is one of the most common fluids on the market. Most GM and Ford units, as well as many imports, call for this type of ATF. If your owners manual recommends any form of Dexron or Mercon — other than Mercon V — this is the fluid you want.
3. HFM-Style Fluids — HFM stands for Highly Friction Modified; it’s a fluid that provides different friction characteristics than Dexron III/Mercon. This fluid appears under a number of different names, including Chrysler’s ATF+ — also called 7670. Other manufacturers that use HFM ATF include:
- Honda/Acura
- Jeep/Eagle
- Hyundai
- Toyota/Lexus
- Saturn
- Sterling
Are these fluids interchangeable? They should be… logic dictates that they are. But to be safe, always use the specific fluid the manufacturer calls for.
4. Synthetic Fluids — A number of manufacturers have begun to discontinue using organically-based fluids in favor of synthetic fluids. Preliminary tests indicate that most synthetics have similar friction modification characteristics to Dexron III/Mercon, but with improved resistance to heat, cold, oxidation, and sheer. Put simply, synthetics last longer.
Synthetic oils are one reason many manufacturers are eliminating the transmission dipstick. Their feeling seems to be the ATF will last longer, so there’s no reason to let people interfere with the transmission and its operation. Will synthetics really keep the transmission operating longer without human intervention? Only time will tell.
CAUTION — Ford labels their synthetic fluid Mercon V, which can be a bit confusing. If the manual says Mercon V, it’s calling for the synthetic fluid; if the name is Mercon without the V, that’s the regular Dexron III/Mercon ATF.
Still not sure which fluid you need? Stop by Pro Trans at 1113 Center street; they’ll be glad to check your car, and tell you exactly which ATF you should be using.
Pro Trans specializes in transmission and drivetrain repairs and service, serving the Redding area. Pro Trans is a member of ATRA — the Automatic Transmission Rebuilders Association — and adheres to its requirements for honest, reliable, quality service.
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