GM Transmission:

• 17MM Wrench
• 5MM Allen Wrench
• 6-8 Liters DEXRON XI ATF

ZF Transmission:

• 4-5 Liters Lifeguard 6 ATF
• 8MM Allen

Also:

• 8MM Socket
• 3/8 Ratchet
• Liquid Penetrant
• Drain Pan

Ensure you conduct this DIY on a vehicle with a cold engine.

It is highly recommended to spray both the transmission drain and transmission fill plug with a liquid penetrant, to break any rust and avoid stripping either plug. Allow liquid penetrant to sit 30 minutes to an hour.

Using a 17MM open-ended wrench, turn the transmission fill plug counter-clockwise to loosen. DO NOT REMOVE THE DRAIN PLUG FIRST.

Using a 5MM Allen Key, loosen the transmission drain plug turning it counter-clockwise.

After verifying both the transmission drain plug and the transmission fill plug loosened with no issues, place your drain pan to catch the fluid.

It is highly recommend you use some sort of clear container to measure and safely store the transmission fluid you drain. Having an accurate measurement of the fluid you remove will mitigate under/over-filling.

Remove the 8MM bolt securing the undercarriage cover. This will give the undercarriage cover enough slack to be pulled back, so the transmission fluid doesn't splash on it.

Remove the transmission drain plug.

Allow your transmission pan to drain until there is absolutely no more fluid coming out. This will ensure the maximum amount of new fluid can be added.

Re-install the drain plug by hand-threading it into place, then using a 5MM allen key to torque it to 10ft-Ibs.

Remove the transmission fill plug we previously loosened with the 17MM open-ended wrench.

A Hand-Held Transfer Pump will be the most ideal tool to transfer new ATF into the transmission. They can be purchased for relatively cheap, but attached above is the one we recommend.

Route the 'IN' hose of the transfer pump into the new ATF jug and the 'OUT' hose into the transmission fill hole.

Only approved DEXRON XI ATF Fluid can be used in the GM model transmissions and only ZF Lifeguard 6 (or equivalent) ATF Fluid can be used in the ZF Transmission.

GM Recommended

ZF Recommended

It is highly recommended you use a friction modifier after doing a transmission fluid change to increase ATF longevity and prevent transmission slipping, shuddering, etc.

GM Transmissions

ZF Transmissions

Pump the new ATF additive and fluid and into the transmission utilizing the handheld transfer pump.

Continue to fill the transmission until transmission fluid starts to stream out of the transmission fill plug.

Once ATF fluid starts to stream out of the fill plug, remove the transfer hose and re-install the transmission fill plug.

A BMW OBD-II scanner is required to read the transmission temperature. Bring the BMW OBD-II scanner to the transmission temp menu and keep it on standby as you will still need to fill with more ATF fluid.

Turn on the vehicle's engine to circulate the transmission fluid, so you can finish up filling the transmission accurately.

The transmission temperature must be exactly within the threshold of 30C to 50C to accurately fill the transmission.

With the transmission within the 30C to 50C threshold, remove the transmission fill plug to finish filling with ATF fluid.

With the transmission within the 30C to 50C threshold, continue pumping the transmission with new ATF fluid.

Continue to fill the transmission until transmission fluid starts to stream out of the transmission fill plug.

Once ATF fluid starts to stream out of the fill plug, remove the transfer hose and re-install the transmission fill plug.

With the vehicle still running, shift through all gears to distribute the new ATF fluid throughout the entire transmission system.

Test drive your BMW to ensure the transmission is functioning properly, without any slippage, shuddering, hard shifts, etc.

Good job draining and filling your ATF fluid! Be sure to service your transmission fluid every 60,000-80,000 miles.