Hello mb world !!! I am new here on the forum. Glad to be here and I appreciate any advice ....My E 63s I bought used with 34k lease return. was not able to be put in drift mode since day one And I would hear a knock noise when turned on in the middle of the car under my thigh area .I took it to the dealer and they confirmed the sound and also confirmed the brake assist light was on and soon after the check engine light turned on after I left it with my world . They said it was a solenoid and that they had to order a part. After it was replaced They still couldn’t put it into Drift mode and sound persist . Now they are working on the valve body they said and I would be getting a free transmission service out of this but my car has been in there for A week now . Anybody have any idea what could be wrong or have gone through the same experience thanks in advance