Where is the transmission oil filler port located on the BMW E90?
2 Answers
The transmission oil filler port on the BMW E90 is located at the bolt on the left side near the rear of the transmission, while the drain port is at the bolt on the oil pan. Precautions for changing transmission oil: The oil level can only be checked when the engine is off, the vehicle is parked on level ground, and the transmission must be cold. Remove the filler plug to check the oil level; the transmission oil should be at the bottom of the filler hole. If the oil level is low, add transmission oil until it starts to overflow from the filler hole, then reinstall the plug. Replacement interval: Under normal circumstances, the transmission oil should be replaced every 40,000 kilometers or once a year as part of regular maintenance. During the first maintenance, if you are not careful, the 4S dealership may not proactively replace it.
When I was tinkering with changing the transmission fluid on my old E90, I did some research on this. Most BMW E90 models require working from underneath the car, with a dedicated fill hole located at the mid-rear of the transmission. You'll need to lift the car and remove the underbody panel first. You'll then see a hex socket screw on the side of the transmission, usually with a copper washer. Be careful not to confuse it with the drain plug! The fill hole is positioned higher up, and there might be electrical connectors nearby. For manual transmissions, it's located below the gear lever, while for automatics, it's hidden beside the oil pan. I recommend using a specialized funnel with a flexible hose to slowly add the fluid. After filling, start the engine and cycle through the gears. Wait until the fluid temperature reaches 40 degrees Celsius before checking the level – fluid should start dripping from the screw hole when it's full. The whole process is safer with two people working together.
