You are unlikely to get any help from the dealer, since you didn't purchase it from them. Looks like you got a better deal at an independent, fair enough. Have you asked your independent broker to pay something towards your transmission, given that they made the profit on the sale? I don't think you would have any luck, but it illustrates the point that you chose not to purchase from a dealer, and not to have your vehicle serviced at the dealer since then. Asking for a policy or goodwill contribution from a dealer will always work better if you are a customer of that dealer.

Given how thin margins are in the dealer business, as nice as it would be for them to recognize your long time BMW loyalty, it just isn't going to happen.

Do you think that Mercedes or another manufacturer would be different in this case?

Also, don't pay the 10k to fix it at the dealer, go to a transmission shop and get it overhauled. Don't bother with a fluid change IMO.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue