France
Hello everyone,
I am facing an issue with my 2003 BMW Z4 E85 3.0i equipped with the SMG gearbox.
Aside from this specific issue, the transmission works absolutely wonderfully. Once 1st gear is engaged and the car is moving, the gear shifts are perfect and smooth.
However, when it gets very hot outside or when I'm stuck in a traffic jam, the clutch often slips significantly in 1st gear, especially when starting on an incline or crawling in traffic.
Recently, in a heavy traffic jam, it got much worse: the transmission completely skipped 1st gear and shifted directly into 2nd. The car was able to move in 2nd for a bit, but as soon as I shifted to Neutral (N), it refused to engage any gear at all, leaving me completely stranded.
Interestingly, I don't have any warning lights (no yellow/red cog light on the dash yet). After letting the car cool down for about 30 minutes, the system recovered and allowed me to drive again.
Given that it works perfectly under normal conditions but slips and gets stuck in N when hot, what should I look for? Could it be a weak electric pump, a tired accumulator sphere, or an overheating temperature/position sensor?
I would love to hear your thoughts. Thanks in advance for your help!