Hello community, I’m newly registered and have a question directly. I drive a Ford Mustang 5.0 bj 2011. About 1.5 months ago the differential + axle had to be replaced. For this I drove extra to a US car workshop near me. After a few problems with the orders the matching parts had been delivered and installed after 5 weeks from the usa. As far as so good. 4 days ago I suddenly found that the new differential Anfing to surren from about 70kmh So I drove back to the workshop to clarify where the noise came from. After a test drive the journeyman who had installed the differential confirmed to me that the surreptitiously comes from the differential and this must be adjusted. No problem so far I thought. When we were back in the workshop and had already arranged an appointment suddenly the master came to it. After we told him the problem this only meant that they did not have the know how available. a differential setting. He must first see if he finds someone externally who can do this at all. Now this sounded to me as I have to cover the cost of it. Can someone tell me how here the legal situation is? I think because they have installed a new part for me you also have to make sure that it works?