Start with fluid and filter but you can also bring it in and have the codes read by the dealer. That's the best way to diagnose it. In fact, if you have the dealer do the fluid change they may just read the codes for you for free when they have it in there basically offsetting the cost of the labor for changing the fluid. Plus, if it turns out to be something internal to the transmission it will save you having to pay for 8-9 more litres of the $15/L fluid to get it corrected.

As much as I hate to say it the 722.6 transmission is one of the areas I would say a good honest dealer can actually save you heartache and trouble by bringing it to them for diagnosis. If you can find a good, honest dealer that is.

If you do the fluid change yourself make sure you use only the correct M-B fluid.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz