$3,000 at minimum is what you’ll pay for a BMW 5 Series transmission replacement cost.
In some situations, you could pay up to $7,000 for a new transmission. Yes, it’s super expensive! Why so much? Some models require more work to replace the transmission, and some cities charge more labor. It’s all a complex calculation.
While it sounds like your mechanic’s quote is within the appropriate range, it’s always a good idea to call around and get multiple quotes.