1. It is NOT a "lifetime" transmission. Change the fluid and filter at LEAST every 100,000 miles, I prefer 60.000.
2. The sticker is right there in the engine compartment from the manufacturer, it says "Use Mobil1 0w40". It's really just the MB spec for the M112 engine that matters.
DO NOT PUT ANY STORE BRAND CHEAP 30W IN IT !!!!!!!