Automotive Maintenance And Detailing


Automotive Maintenance And Detailing

What is Automatic Transmission Fluid?.

 The transmission of the vehicle has been developing for a long time since the first car was born. The automatic transmission was born around the 1940s and has a long history developing until today. It needs the special automatic transmission fluid to move the internal gears and the related parts besides the power of the car engine. As you can see in the Power Steering System guide, The power steering system uses the same fluid as an automatic transmission. 

The transmission fluid is using for gear shifting, lubricating, and it is a necessary component to transfer engine torque to the wheels. Because of this, the transmission fluid is a kind of hydraulic fluid.

This fluid has a red or green color for distinguishing it from the engine or other oils. Moreover, it has less viscosity than engine oil, too. The manufacturers have researched and developed their products to meet the specification of a modern car that has more power and runs faster. They 

will add the additives for multi-purposes such as anti-rust, reduce wear and corrosion of internal parts, or additive to help cleaning metal surfaces in the fluid.

The carmakers either develop or certify the transmission fluid of the manufacturers. Ford, GM, Chrysler, and others have certified the fluid grade for their transmission, and they have specific product codes. There 

are some examples Dexron ULV: GM, Mercon V: Ford, DW-1: Honda, AW-1: 

Volvo, Toyota ATF WS: Toyota and so on.


What is causing the fluid to deteriorate?

The transmission fluid will turn to a dark red color when the vehicle runs for several thousand miles. However, many carmakers use “lifetime fluid” for their car transmission. As the theory, it may consider that the fluid is lasted long without changing.

The fact is the transmission fluid will deteriorate if it is mix with air or oxygen. Moreover, dust and debris of metal gears or small particles of clutch pads could cause of dirty fluid. The dirty fluid could clog in the transmission module and solenoid valves. The outcome is malfunctioning automatic transmission such as jerking, no shifting, or else.

For the above reason, the transmission fluid would not or less deteriorate if the gearbox has a complete seal. Then the manufacturers try to make a good seal by do not have the dipstick for fluid check or have a well-sealed filler plug, but it is not possible in the real world situation.

The transmission needs an air vent to decompress or balance the pressure inside the gearbox case. Otherwise, it will cause the gasket leak. It will have a transmission ventilation tube or port on the gearbox case.

Of course, it has a perfect sealed as much as they can design but the different driving conditions like hot, rain, dust. The moisture could damage its seal, and the dirt will contaminate into the fluid soon. It is not only this seal, but the drive shafts seal, as well.

That’s why you should have a transmission fluid check after driving on a flooded road. The fluid contaminates with the water will have a pinky color. You will need to drain it out immediately.

how often do you need to change fluid?.

The lifetime fluid could use up to 100,000 – 120,000 miles. That means a lifetime of vehicle or transmission. We recommend having an interval check and replace every 30,000 – 50,000 miles since the fluid cost is a lot less than repair cost or a brand new transmission cost.

How to consider when to check and replace?. You would have it checked if you drive the car in a normal circumstance like driving a passenger car on a regular road, no more load or towing, and on the limit speed. In this case, you could forget to change the new fluid, as the theory. However, we still recommend to have it changed, but a little more extended from a regular check interval. It could be every 50,000 – 70,000 miles.

On the other side, if you use the vehicle like a workhorse or two shifts production machine, you need to replace the new fluid every recommended mileage, 30,000 – 50,000 miles. The transmission in this day vehicle is installed with an easily changeable filter, for example, the dual-clutch type from Ford. You would replace it every time of fluid changing.

How to check and do transmission fluid change?.

 As we mentioned, most transmissions have no dipstick to check the fluid. You have only one method is completely drain it out and fill a new transmission fluid. The car’s owner manual has information on the fluid type, name, code number, and quantity, as you can see in the below picture.

You can have the car dealer service to do a new transmission fluid change if you insist on doing this before its interval maintenance schedule. They would not deny your requirement as they can sell their product and a labor cost, except they have a tight maintenance queue of other customers’ cars.


Prepare equipment:
– Plastic trays and empty gallons for old fluid
– Rubber gloves
– The pieces of rag
– Ratchet wrench for transmission fluid drain plug, bolt
– If any, a new washer for the fluids drain plug, bolt

  Park your car on the level surface and jack up the front of the vehicle. For safety reasons, insert the jack stands under the car securely. We don’t 

recommend using the car jack instead of the jack stand. 

1. Wear the gloves and start by removing the transmission fluid filler cap on the engine

2. Remove the bolt of the fluid pan under the car with the wrench

3. Use the plastic tray to collect old fluid, drain it out until it has no more oil drops. If your vehicle has a transmission fluid cooler, you need to drain it out of the cooler, too.

4. Remove fluid filter, if any, using the filter wrench

5. Install a new fluid filter. We recommend you fill a new fluid in the filter and lubricate some on its rubber seal before installation if it installs in a vertical position.

6. Screw back the fluid pan bolt with a new washer. You would replace a new bolt washer every time to prevent the fluid leak.

7. Looking for a drain plug on an upper side of the transmission case, 

this drain hole is for a fluid level check when you refill a new fluid. 

Remove the plug.

Automatic transmission fluid level check plug

8. Fill in a new fluid until it pours out from the drain hole of step 7.

9. Screw in the bolt of step 7

10. Recap securely of the fluid filler cap.

11. Start the engine and check leakage at the fluid filter and both fluid drain bolts.

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