How to Change Transmission Fluid: A Practical Gearbox Guide

Transmission fluid is very important in helping to ensure that the gears inside the gearbox continue to work properly. This fluid works to keep the inside parts lubricated and to deal with any excess heat and, in automatic gears, it also helps to facilitate gear changes through hydraulics.

As time goes by, the transmission fluid may get dirty or not be as effective anymore. Changing it is more complicated than just draining the old oil and putting new oil in since the right oil and how to go about changing it will differ from one car to another.

It is important to check out the service manual for your specific model before attempting to do anything with your transmission. QLD Auto Parts can help with this if you need help in identifying the right oil and gear box parts.

What Does Transmission Fluid Do?

The transmission fluid does a number of things in a gearbox. These include minimizing the friction between moving parts, controlling operating temperature and doing hydraulic work in some automatic transmissions.

However, manual and automatic gearboxes do not need to use the same transmission fluid. There are cars that use ATF whereas there are others that may need manual transmission fluid, gear oil or manufacturer’s specification fluid.

Using the incorrect transmission fluid will result in improper functioning or even damage to the gearbox hence the need to specify the correct specification at the onset.

When Should Transmission Fluid Be Changed?

Not all vehicles use a universal interval. While some vehicle manufacturers recommend the fluid replacement based on certain mileage or time periods, others may require that you inspect and not necessarily replace the fluid.

Your driving style will influence the condition of the fluid too. For instance, frequent towing, carrying loads, city driving, and hot weather may put more pressure on the transmission.

Refer to your vehicle’s manual to be sure about the recommendations for your car.

Signs Your Transmission Fluid May Need Attention

Fluid condition alone does not diagnose every transmission problem, but certain symptoms should not be ignored.

Possible warning signs include:

• Delayed engagement when selecting a gear
• Harsh or unusual gear changes
• Transmission slipping
• Unusual whining or humming sounds
• A burning smell
• Fluid leaking underneath the vehicle
• Dark or contaminated-looking fluid

These symptoms can have several causes, including mechanical faults. Simply replacing the fluid may not solve an existing transmission problem.

What You Need Before Starting

If your vehicle’s manufacturer allows a fluid change using a straightforward service procedure, prepare everything before beginning.

You may need:

• Correct transmission fluid
• New transmission filter, if applicable
• Replacement gasket or sealing components
• Drain pan
• Socket or suitable hand tools
• Funnel or approved filling equipment
• Vehicle stands or lifting equipment where required
• Gloves and protective equipment
• Container for the old fluid

The specific type of equipment will depend on the car model. Certain transmissions today need a particular temperature for fluid fill.

Call QLD Auto Parts on 04 3350 3503 to enquire about current used transmission or gearbox availability.

Step 1: Identify the Correct Fluid

Check your owner’s manual or manufacturer’s specifications for the correct transmission fluid and quantity. Using the wrong fluid can damage the gearbox.

Step 2: Prepare the Vehicle Safely

Park on a level surface, apply the parking brake and use proper vehicle stands if lifting is required. Never work under a vehicle supported only by a jack. Allow the transmission to cool before starting.

Step 3: Locate the Drain and Fill Points

Drain plugs, fill points and dipsticks vary between vehicles. Confirm each component before removing it, as some transmissions require a specific filling temperature or procedure.

Step 4: Drain the Old Fluid

Place a drain pan under the transmission and remove the drain plug. Check the old fluid for unusual colour or metal debris. If fitted, replace the transmission filter as recommended.

Step 5: Refit the Drain Plug or Filter

Install the new gasket, seal, filter or drain plug as required. Tighten it to the manufacturer’s torque specification to prevent leaks or damage.

Step 6: Add the New Fluid

Add the recommended fluid through the correct filling point. Do not rely only on the amount drained, as some old fluid may remain inside the system. Avoid overfilling.

Step 7: Check the Fluid Level

Follow the correct checking procedure for your vehicle. This may involve using a dipstick, keeping the vehicle level or checking the fluid at a specific temperature.

Step 8: Check for Leaks

Inspect the drain plug, filter area and seals for leaks. If you notice unusual noises, warning lights, fluid loss or poor gear changes, stop driving and arrange a professional inspection.

When Should You Get Professional Help?

In case the transmission does not have a straightforward maintenance process, needs to be filled according to the temperature or has a special electronic measuring system, then it might be more appropriate to take it to a specialist.

The fluid replacement will not fix any worn gears, broken clutches, solenoids, or other internal parts of the transmission.

In case the transmission is slipping, making strange sounds, or not engaging properly, first identify the real cause of the problem.

Looking for a Replacement Gearbox?

In some cases, the transmission problems can be more severe compared to those relating to the service of the transmission fluids. In the case of old vehicles, using the used gearbox may serve as a feasible solution to the problem of replacement.

The disassembles suitable cars and salvages suitable parts for further reuse, including the transmission parts, depending on their availability.

When seeking a used gearbox, please indicate the vehicle brand, model, year and the transmission type.

Final Thoughts

Replacing the transmission fluid is a critical process for maintaining your car, although doing so the right way will depend entirely upon which type of gearbox is installed in your vehicle.

First, however, find out which fluid is the right one, and be certain that you understand how to drain and fill the transmission.

In case you are not confident about the process or the transmission in your vehicle is already malfunctioning, it will pay off to seek professional help to avoid having your relatively cheap maintenance turn into expensive repairs.