ML55 tranny & foul exhaust odors
 

My 2002 ML55 (10k miles) is giving me fits. I've tried Shell, Amoco, Phillips 66, and other premium gases. ALL cause a very foul (sulpher?) odor to come ito the passenger compartment whenever I have the rear vents open. The dealer says there is nothing wrong - no "codes" found on their computer. Also, if I back up out of a parking spot and throw it into 1st gear, the tranny doesn't engage right away. Again, dealer says no problem because no "codes" found. Help??

The sulfur is coming from your engine running rich and having fuel being burned in the cats. Both cats need to be replaced, o2 sensor and MAS Sensor and perhaps the mufflers too. Take it to another dealer and tell them, I dont want my car back till the problem is fixed and be sure to get a loaner. I had the same problem on my 99 S420. As far as transmission, if there is no codes the dealer does not want to be opening the trans up.