How to change oil for automatic transmissions

How to change oil for automatic transmissions

Meyle shares its knowledge on the need to change oil in automatic transmissions, and provides a step-by-step guide on how to do it.

Although the misconception that automatic transmissions don’t need an oil change was debunked long ago, it has proven to be quite persistent. Transmission oil undergoes a natural ageing process, with the oil wearing out and additives diminishing over time. Therefore, it’s all the more important to change the oil, as it prevents damage to the transmission, and maintains transmission function and driving comfort.

Based in Hamburg, spare parts manufacturer Meyle offers over 60 oil change kits, which come with all the components required for an oil change: a filter, seals, screws, drain/intake plugs, magnets and the amount of transmission oil the application calls for. This reduces stress and saves money – for workshops and drivers alike.

How to change oil for automatic transmissions

Amongst other things, Meyle offers an oil change kit for the Mercedes 7GTRONIC and 7G-TRONIC PLUS 7- speed automatic transmissions. It contains the special CombiMedia and SmartMedia triple hydraulic filter, which complies with code A89 (reduced friction), as specified by Mercedes. Tailored to individual vehicle applications, the multilayer construction ensures optimal filter performance, with various filter media ensuring that the particles that are formed in the transmission are captured. Here, Meyle shows how to change the transmission oil for automatic transmissions in four steps, but also insists upon observing the vehicle manufacturer’s specifications first.

Step 1 – Preparation

Before you begin, bring the transmission oil to operating temperature, shift the gear to N and turn the ignition key to position 0. Following this, lift the vehicle with the lifting platform and ensure that it remains level, as this will enable correct filling and oil level measurement.

Step 2 – Draining the transmission oil

For vehicles with stop-start function, first loosen the plug connection of the additional oil pump. Then, remove the drain plug and drain the transmission oil. After opening the drain plug, break the overflow pipe and drain additional ATF oil to prevent the oil from gushing when removing the oil sump.

Next, for vehicles with the stop-start function, remove the additional oil pump of the automatic transmission. Once the transmission oil is fully drained, turn the motor in the direction of motor rotation (second person) to access the drain plug of the torque converter. Remove the drain plug of the torque converter and drain the remaining ATF oil, and then tighten the M8 drain plug to 10Nm torque.

Step 3 – Replacing the hydraulic filter

First, remove the oil sump. Be careful, as the oil sump contains a residual amount of ATF oil. Then, remove the hydraulic filter and clean the oil sump. Once the oil sump has been cleaned, install the new magnets and overflow pipe as well as the oil sump seal.

How to change oil for automatic transmissions

Now it’s time to insert the new, friction-reduced SmartMedia high-performance hydraulic filter from the Meyle-Original oil change kit. Once the filter is in place, resecure the oil sump. Set the torque wrench to 4Nm and tighten the oil sump screws crosswise. After doing this, tighten all the oil sump screws crosswise with a 180° rotation angle. According to guidelines, oil sump screws may only be used once. Screws which have been used once may not be used again. Before reattaching the additional oil pump, the seal connections on the suction and discharge sides should be checked for any damage and, if necessary, replaced. Following this, insert the additional oil pump, tighten to 8Nm and reattach the plug connection of the additional oil pump.

Step 4 – Refilling the transmission oil

In the final step, the automatic transmission is refilled with transmission oil. Fill the filling device with 8L of new ATF transmission oil and attach the special adapter for filling the transmission. Now, fill it with 6L of transmission oil, and then start the engine in P and connect the diagnostic unit to determine the transmission oil temperature.

Filling part 1: Once the transmission oil has reached a temperature of 45°C (testing temperature for vehicles without additional transmission oil cooler), add the remaining ATF oil with the engine running. If a constant stream of oil flows back at the specified oil temperature, the temporary filling level has been achieved. Now, remove the filling adapter and shift to gears P, R, N and D for six seconds each time with the brakes applied, and then shift back to gear P.

Filling part 2: Now, check the transmission oil level again as described in the previous step, maintaining a transmission oil temperature of 45°C (testing temperature for vehicles without additional transmission oil cooler). You may need to turn off and restart the engine to reach the correct testing temperature.

Now, close the system at the filling opening (oil sump) using a new drain plug, and seal and tighten to a torque of 22Nm.

How to change oil for automatic transmissions

Meyle Tip

The transmission oil temperature must not exceed the specified temperature of 45°C, as the overflow pipe in the oil sump is designed for this oil temperature.

For more information, click here.

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