How to Add Gearbox Oil to Your Car

Gearbox oil is essential for lubricating the car's transmission system. To select the correct type, you must know the car's make and model, as well as whether it’s an automatic or manual transmission. It’s best to refer to the owner's manual and follow the instructions regarding oil level checks and the oil filling process. Some manufacturers don’t provide the usual dipstick. Below is the most common process for checking and adding oil to your car's gearbox.

Start the car. To get an accurate gearbox oil level reading, you should check the oil while the transmission is running and the oil is warm. Park the car and engage the handbrake while you check the gearbox oil. Note that some vehicles require the oil to be checked in the ‘N’ gear position. Refer to your owner’s manual for the proper gear setting when checking the oil level.

• If you've been driving for 30 minutes or more, it’s recommended to turn off the engine for a few minutes before checking the gearbox oil to let the oil cool down.
• Note that some cars allow the dipstick to read results in a “cold” state. Even if your car falls under this category, it’s still advisable to start the engine and allow the gearbox oil to warm up before taking the reading.

Start the engine without driving the car, release the handbrake, and shift the gear lever through all positions, including forward and reverse. If you check the gearbox oil when it is cold—meaning the engine isn’t running and the gear lever hasn't been cycled through all positions—the dipstick will provide an inaccurate reading. The result will show that the gearbox oil is overfilled. To avoid this, shift the gear lever through all positions to ensure the oil circulates evenly.

Open the hood and locate the dipstick. Remember to engage the handbrake, especially if you leave the car in gear when exiting. In some vehicles, it’s easy to confuse the oil dipstick with the gearbox oil dipstick, so you need to be clear on the gearbox’s location.

• Look towards the rear of the engine, near the firewall. This is where the gearbox is located in most rear-wheel drive vehicles.
• In front-wheel drive vehicles, the gearbox dipstick is usually located closer to the front of the engine, connected to the gearbox. However, this may not apply to all car models, so it’s essential to consult the user manual or check for labels on the dipstick to identify the correct one.

Dip the stick into the gearbox oil compartment and pull it out to check the result. Now you can see how far the oil level reaches. Be sure to compare the actual oil level with the 'hot' oil mark on the dipstick.

Keep the engine running with the gear lever in 'N' and the handbrake engaged. It's recommended to keep the engine running while adding oil to the gearbox, but make sure the car is in 'N' and the handbrake is applied for safety.

Check the owner's manual to determine the type of gearbox oil you need to buy. The manual will specify the type of gearbox oil your vehicle requires and provide any special instructions for adding oil.

• The dipstick itself may also indicate which type of oil is needed. Keep in mind there are various types of gearbox oil, each with specifications suitable for different vehicles.
• Look for guidance on how often to change the gearbox oil. While you can top up the oil when the level is low, many manufacturers recommend changing the oil every 48,000-160,000 km, depending on the make and model of the car.

Insert a funnel into the dipstick hole of the gearbox. Most cars require a long oil-filling funnel.

Pour the oil slowly into the funnel. Add the oil in small amounts to avoid overflow. How much oil do you need to add? This depends on what you're doing:

• Are you topping up the oil? If the oil level is slightly below the mark on the dipstick, start by adding 1/2-1 liter of oil. Recheck the oil level and add 1/4 liter (or less) at a time until it reaches the full mark.
• Are you removing the gearbox pan and replacing the filter? This maintenance usually requires around 4-5 liters of oil to replace the lost oil.
• Are you replacing all the gearbox oil? You will need about 9-13 liters of oil to replace the entire oil supply.

Release the handbrake and cycle the gear lever through all positions while the car is stationary. This step helps circulate the oil and ensures an accurate oil level reading.

Check the oil level one more time. You might not need to add more oil, but if necessary, add small amounts. At this stage, most cars will only require less than half a liter of additional oil.

Return the dipstick to its original position and make sure it’s securely in place. You may need to twist it until it locks or press the latch on the dipstick’s top to secure it.

• Ask a mechanic to check the gearbox oil whenever you take the car for servicing. If you're not familiar with adding gearbox oil, it's better to have a mechanic do it.
• Some gearboxes don’t have a dipstick for checking or adding oil. Manufacturers often call this a tamper-proof design. They want the gearbox oil to be checked and replaced only during major maintenance intervals. Some manufacturers may even prefer that you don't change the gearbox oil yourself. Always follow the manufacturer's guidelines for checking and servicing the gearbox.
• Follow the recommended frequency for changing the gearbox oil as stated in the owner's manual.

• Be cautious when purchasing the gearbox oil for your vehicle. Using the wrong type of oil can damage the car, and your insurance may not cover repairs for this issue.
• If you frequently need to top up the gearbox oil, consider asking a mechanic to check the gearbox. If the oil is regularly depleting, there might be a leak in the gearbox.
• If you don’t flush the gearbox according to the recommended schedule, it will wear out faster. If your gearbox works hard or your car regularly carries heavy loads, you should change the gearbox oil more frequently.

• Cloth for wiping
• Gearbox oil
• Owner’s manual
• Oil funnel