car - 1997 E420

i'll be doing engine oil, ATF, differential, coolant, cabin filters, air filter and a new wiper. thanks to the fantastic DIY articles on engine oil & ATF changes, those will be fine. But i couldn't find any articles on diff fluid & coolant changes. Are these straightforward? 2 plugs in the differential and a petcock for the coolant? if there are any special precautions i should take plz let me know. what sockets are required to access all the plugs? thanks!