I wouldn't bother deviating from what Mercedes said to put in it.

ATF3 superseded 2, and 2 is basically non-existent in the US. All my manual gearbox Mercedes that call for an ATF fill I put Dex3 in because that is what is available with no problems.

As for the diff, it doesn't make any sense to put way thicker oil in just to do it. Straight 90 can be tough to find sometimes, I put 75/90 or 80/90 in mine with no issues. I think eventually Mercedes spec'ed an 85/90 which you can buy from the dealer but its fairly expensive, I only run that in my more expensive cars.

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68 280SL - 70 280SL - 70 300SEL 3.5 - 72 350SL - 72 280SEL 4.5 - 72 220 - 72 220D - 73 450SL - 84 230GE - 87 200TD - 90 190E 2.0 - 03 G500

Nissan GTR - Nissan Skyline GTS25T - Toyota GTFour - Rover Mini - Toyota Land Cruiser HJ60 - Cadillac Eldorado - BMW E30 - BMW 135i