[Rababah]

I own a 2018 BMW F30 330i xDrive. Recently, I had the transmission oil changed. The car was lifted, and the oil was filled properly. After the procedure, the technicians left the car running while elevated for about 20 minutes.

Since then, I’ve been experiencing an issue with the speedometer. When driving normally, the speed reads correctly 100% of the time. However, when I press the accelerator suddenly or when I’m driving steadily and then release the pedal, the problem occurs. For example, when I’m driving at 80 km/h, the speedometer suddenly jumps to 120 km/h, even though the car is still moving at 80 km/h according to the onboard computer and Google Maps. Afterward, the speed remains stuck, with a discrepancy of around 40 km/h from the actual speed. To reset it, I have to bring the car to a complete stop, and then the speedometer returns to normal.

However, the issue reoccurs within seconds once I resume driving, making the driving experience uncomfortable and concerning.

[scubajim]

Was it a simple drain and fill or a power flush, which is not recommended. Maybe get them to recheck the fluid level. Why leave it elevated and running for 20 minutes? There is a specific procedure for the fill. Transmission has to be at a specific temperature before its topped off. Are you sure that was performed correctly? Very strange.