Maintenance tips: This is how to do proper automatic transmission clean

Updated Aug 16, 2022 | Same topic: Handy Maintenance Tips

The transmission is one of the most expensive parts to maintain. But do you know how to properly clean the automatic transmission?

Keeping your vehicle in good condition is not an easy task, yet it still part and parcel of vehicle ownership. But did you know you can actually perform a number of maintenance procedures by yourself?

Take the automatic transmission for example; it’s one of the most sophisticated mechanisms on a car, as well as the most expensive to maintain.

Yet you can undertake cleaning the automatic transmission in order to keep it shifting as smoothly and as efficiently as possible, with a little help from

Step 1. Get the vehicle ready for service

In order to properly clean your car's automatic transmission, you’ll have to get it ready by driving the vehicle around; this will warm the transmission fluid just enough to let it drain out faster and easier. A few minutes on the road should be enough to raise the gear oil’s temperature without letting it run too hot.

Man driving the car

Prep the transmission by driving the vehicle around for a few minutes

>>> Worth reading: Traffic in the Philippines & your automatic transmission.

Step 2. Pick a workspace

You’ll need an ideal space that’s free from clutter and not easily accessible by children and pets. A dedicated garage would be ideal and have extra light sources ready.

Avoid working on the side of the road, where an accident might occur. If no garage is available, pick out a private spot such as a clear backyard with a flat surface made of concrete.

Park the car on the work area, taking care to engage the parking brake and put a wooden chock against the rear wheels as an added precaution.

car garage

A dedicated garage would be good, but make sure you have extra light sources on hand

Step 3. Mount the jacks

Find a good jacking point on either side of the under-chassis to raise the car and give you a good view of the transmission underneath. The car’s user manual will be most helpful with this step; a diagram should be present, indicating where you can best put the jacks.

Follow the directions carefully, making sure that each jack is securely in place.

Woman reading car manual

If you have your manual, there should be a diagram on where you can best put the jacks

>>> Read more: How to troubleshoot a failing transmission.

Step 4. Drain the fluid out

Look for the drain plug in one of the corners of your car's transmission oil pan. Before you remove the plug, make sure that you have something to catch the fluid as it drains out, such as a large metal basin. This will keep your working area clean and safe.

Some manufacturers design the oil pan in such a way that it doesn’t use a drain plug. If that's the case, you will need to remove some of the bolts that hold the pan in place. Loosen all the bolts, but only remove those on one side, where the transmission fluid will flow out.

Once all the fluid has run out of the reservoir, you can remove the transmission pan entirely.

Drain plug of the transmission

Look for the drain plug in one of the corners of your car's transmission oil pan

Step 5. Examine the transmission fluid

Put some of the drained transmission fluid in a transparent beaker and look closely, searching for sediments or bits and pieces of metal. If you see anything out of place, then that could indicate a worse problem at hand. If you find pieces of metal in the liquid, or if the liquid itself id dark-colored, then it may need to be replaced with fresh gear oil.

Tranmission fluid

Put some of the transmission fluid in a transparent beaker and take a good look at it

>>> Also check: The ins & outs of car transmission and drivetrain.

Step 6. Clean the transmission oil pan

After removing the oil pan, clean it on the outside using a degreaser while using a brake cleaner on the inside. Automatic transmissions are hypersensitive to foreign elements and dirt, hence the need to give it a proper wash-down. For gasket material stuck to the transmission oil pan, you can remove them using a razor blade, doing the same to the transmission's mating surface.

Metal particles can also get stuck if there's metal installed on the transmission pan. Clean this thoroughly and get rid of any metal particles that shouldn't be there. Also, consider cleaning the bolts that secure the oil pan to your vehicle's transmission.

car transmission oil pan

After removing the oil pan, clean it on the outside using a degreaser while using a brake cleaner on the inside

Step 7. Remove the transmission filter

Many manufacturers equip their automatic transmission with a filter, which serves to trap debris; over time, impurities can accumulate and impair the filter’s efficiency. You will need to locate and replace this filter, usually at the bottom of the valve's body.

The filter should be a yellowish or white plastic mesh right on the bottom of the filter. Once it has been removed, you can put the transmission pan back into place.

>>> You might concern: Some habits accidentally shorten the life expectancy of transmission.

Step 8. Putting the transmission pan back

This involves working at a low and steady pace. First, apply a light coating of your preferred high-tack sealant to the edges of the transmission plan. Then, use your dominant hand to line the holes of the gasket along the holes of the pan. After that, allow the sealant to set for a few minutes.

Carefully re-install the transmission pan by screwing on the bolts. Refer to your manual and tighten the bolts according to the specifications.

fixing car transmission

You need to carefully put the transmission pan back

Step 9. Finishing the job

Lower your vehicle off the jacks safely and put your tools away. Then, lift the hood and pour in the fresh transmission fluid, taking care that you don't put in too much or too little. Use the dipstick to guide you in pouring the right amount of fluid.

Switch on your engine and let it idle for a few minutes to let the new transmission fluid circulate properly, and you’re done.

>>> Click here to get more helpful tips and advice for car owners.

Hanna Sanchez

Hanna Sanchez


Hanna is one of the most competitive swimmers in the country during her day. It was not long before she discovered her passion for the automotive industry as well. Nowadays, she balances her passion through writing as well as coaching.

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