One of the weakest points in the Mercedes S-class (W221) is the 7speed gearbox 7G Tronic. The most common problem is with the box control unit (meechatronics). In some cases, the problem is solved by reprogramming the unit, but it is very often necessary to change the entire node in the collection. The problem is complicated by the location of the metatron directly in the oil crankcase, so it is difficult to get to it. Also, failures are often occurring with a hydrotransformer. 5-speed automatic box AMG SPEESHIFT is the least problematic node, and there is hardly any criticism.