This is the most important change there is. You want to drain the trans and engine, preferably while they are warm. Clean the magnetic drain plugs real well also. It is going to cost some $ but this gets rid of any manufacturing crap in the engine and trans. Be careful to put the right filters in the right locations. A good diesel oil like Rotella will do for the engine. SUDT2 for the trans. Have a good pair of filter pliers since they like to make them tight as crap at the factory. Good luck.