you need to add it now. and make sure that your gear oil is NOT synthetic. using lucas or stay lube +bottle of friction modifier. find out what brand of gears they put in it. what exactly is Mopar HIPERF gears?
actual breakin of how it was explained to me, in is about 20 minutes of driving and let cool for about 20-30 minutes then for 40 minutes let cool and hour. then change fluid at 500 miles.