Fluids – What’s Up With Transmission Fluid?

If you own a car with an automatic transmission, you may have heard that you need to get regular transmission flushes. The truth is that you can do the job right in your own garage — if you know how to do it properly. During this example on how to flush your transmission fluid we are using a 2008 Ford F150 with the 4R75W transmission, however, the same steps apply to most vehicles. Here is how to flush your transmission fluid safely and correctly to keep your vehicle in top shape.

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transmission fluid

Why Do You Need To Flush The Transmission Fluid?

If you own a vehicle like a Ford F150 that has an automatic transmission, you will need to make sure that the transmission is flushed on a regular basis, especially if you do any kind of regular hauling/ towing. Flushing the transmission ensures that the transmission fluid is pushed through the car’s hydraulic lines to fully remove old fluid as well as debris.

The benefits of flushing the transmission are fairly straightforward. First, it improves the lifespan of your transmission. This is because it reduces the risk of debris clogging the hydraulic lines, putting pressure on internal seals and eventually causing leaks.

Flushing the transmission also improves the way the fluid moves through your car’s system. This directly affects the way your car shifts, making it easier and smoother on the internal clutches within the transmission to shift between gears.

It might also improve your car’s fuel consumption. A transmission that is in top shape affects how well your entire vehicle operates. Improving your car’s shifting can improve your gas mileage, saving you money.

How Often Should You Flush Your Transmission Fluid?

The general rule of thumb is that you should flush your transmission once every 30,000-60,000 miles. This usually translates to once every 2-4 years if the vehicle is your daily driver. However, there are some distinct signs to watch out for that could indicate it is time to flush your transmission now instead of waiting.

How Do You Know When It Is Time To Flush Your Transmission Fluid?

Most of the signs that it is time to flush your transmission have to do with problems during gear shifts. Watch out for the following signs:

  • Noises like rattling or grinding coming from your transmission, especially when the car shifts gears
  • Your car seems to have trouble shifting gears
  • The gear shift seems like it is slipping while transitioning
  • Your car shudders or hesitates after gear shifts
  • Your car surges or shudders unexpectedly

How To Perform a DIY Transmission Flush On Your Ford Explorer

Although there are many steps to performing a transmission flush, the actual process itself is not difficult. If you follow these steps carefully, there is no reason why you shouldn’t be able to do the job without hassle.

To get ready to do the job, raise your car off the ground. You can do this a number of ways, either with floor jacks, ramps, or jack stands. Remove the drain plug within the torque converter, place a drain pan under it, and drain the transmission fluid.

Part One: Draining The Transmission

The first part of the process is to remove the old transmission fluid from your vehicle. This can be challenging, since you will need to make sure that the lines are as empty as possible.

Flush The Cooler Lines

Find the cooler lines in your transmission. Using compressed air, flush them gently. Be sure to keep the air on low pressure; doing otherwise may cause transmission fluid to spray out the other side.

Loosen The Bolts On The Oil Pan And Break The Seal

Using a socket wrench, loosen the bolts on the oil pan. This should cause the seal to break and let fluid move away from the edge of the pan. If this doesn’t happen, use a hammer (preferably a rubber one) to tap the seal lightly until it breaks.

Remove The Bolts

When the fluid finally stops draining, remove the pan retaining bolts. The goal is to continue draining as much transmission fluid as possible.

Clean All The Parts

Remove the gasket, magnet, pan, and mating surfaces. Clean them thoroughly with an approved solvent and clean cloth. Replace the magnet to prepare for replacing the transmission fluid. Then remove the bolts from the filter and the filter itself. You will need a socket wrench to do this.

Once the filter is removed, you can take out any seals and gaskets that need to be replaced in the transmission. Replace the seals, gaskets, and filter with new, clean models. Put your new gasket back on your transmission and use a torque wrench to reinstall the retaining bolts. Make sure to tighten them to 79- to 119-in pounds.

The last part of this step is to put the cooler lines back on and replace the drain plug. Now you are ready to put new transmission fluid in your vehicle.

Part Two: Putting In New Fluid

At this point, the old transmission fluid has been drained from your vehicle and all the parts have been replaced. Now you are ready to put new transmission fluid in. This is the easiest step of the process.

To begin, lower your Ford Explorer to the ground. This last part doesn’t require your car to be elevated.

Remove The Dipstick for Transmission Fluid

Take the dipstick out of your transmission filler tube and put a funnel in to prepare to replace the fluid. Put six quarts of automatic transmission fluid into the funnel.

Check The Engine

Once you have replaced the fluid, it is time to check the gears. Start the engine and put the transmission through the gears. Then put it in park or neutral and let the engine run for about 15 minutes. This will let the transmission and engine reach their usual temperature so you can check that they are functioning under normal driving conditions.

After you do this, use your dipstick to check your fluid levels, adding more as indicated.

Is This Information Applicable To Different Ford Models?

This method of flushing the transmission can be used for all Ford models that use the four-speed automatic transmission. This includes the 4R70W, the 4R75W, and the 4R75E, among others. You can find all the Ford models that have the 4R75W transmission at Reman-Transmission.com.


Author: Luke Wilhoit, Content Contributor, carpartplanet.com & Reman-Transmission.com

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