I am coming due for an oil change and I was going to change the front and rear differential gear oil and the Transfer case fluid as well. I know that the front is listed as SAE 90 rear 85W90 and transfer case is Dextron III ATF. I was thinking of going synthetic on all three. I know that synthetics handle contamination with water better than dino oil. (I have to ford some creeks getting to my favorite hunting spots usually only about 12" of water) I already use Mobil 1 0W40 motor oil and have been happy with their oil so my intention was use all Mobil 1 fluids. But Mobil one only lists a 75W90 and 75W140 for their synthetic gear oil. Will one of these be ok in the ML? Are there other synthetic gear oils that would be better? Mobil has a synthetic Dextron III ATF so that is not a problem. Mine is a 98 ML 320.

Thanks,