The Mercedes-Benz M Class Third Generation (W166), produced from 2011-present, is a luxury sport utility vehicle. The third generation offers increased legroom, and is an award-winning German import. Despite being extremely well received, this crossover SUV has been known to demonstrate a few common issues, such as a rough transmission problem.
Owners have reported that sometimes their Mercedes feels as though it has suddenly slammed into a lower gear. Some drivers have described the sensation as feeling like the vehicle is being rear-ended. Many have reported this problem to occur between ten and twenty miles per hour, and typically it happens when the vehicle is nearing a stop. A loud crash or bang sound may accompany the jolt. Typically, no warning lights indicate these signs and symptoms. Some third generation owners have reported that this issue seems to present itself when tire pressure is low, but others find tire pressure irrelevant to the problem. Regardless, the issue is typically worse when the engine is cold.
The problems behind events like these can be particularly difficult to diagnose, as they can be almost impossible to replicate. It is possible that the transmission control unit needs recalibration. Alternately, the valves could need replacement, your Mercedes might need an entirely new transmission, a software update could remedy the malfunction, or the root of the problem could be something completely different.
In the event of this unfortunate experience, we recommend consulting a local independent German auto shop. These mechanics will be knowledgeable about the third generation’s common problems, yet they will be able to offer affordable advice and solutions. This problem is a safety concern, and for the wellbeing of both you and your M Class, an expert should look at the vehicle right away.
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