altenator or aircon

Dear all, As above, 2007 CRV 2.2 diesel. has 45,000 miles, just wodnering if a transmission oil change is due (rear diff doen not so long ago, with 'burnishing in sansbury's car park....) and if so, how to. is it obvious filler/drain plug type? Also belt that powers altenator etc. it looks a...