Rear Diff

hello;
My rangy has a rear diff that whines,it is more noticeable now as i have replaced today the 2 rear hubs+bearings as well as the two half axles,the splines of the half axles were half worn,so it was a good call to replace them along,
rangy lost some of the ep in the process and i didn't like the color of it,it was between gray and gold black although i have replaced it a couple of months ago,and defo water isn't getting in the rear diff from the seals nor the breather.
My question is,there is defo a whine in the rear diff,i heard it is common on the p38,should i worry and replace the diff?or live with its whining and try to repair something in it?i noticed also that there is a noticeable play in the diff when i jack the rear axle and turn one wheel it turns half an inch before engaging the prop shaft.:doh:
should i expect the diff to blow up,or should i do something about it ?
is it good to go for more 20k with it?

take it out and check brgs before it gets worse,usually front pinion brg goes first

i heard that the p38 rear diff doesn't have bearings inside of it!
and also the wear hits the crown pinion and where the half axles splines meet the diff.could be wrong though

it will be if you dont check the brgs ,its the play that screws the crown wheel and pinion as they run out of line redoing the brgs usually puts pinion back to spec although diff carrier brgs have to be adjusted,obviously anything can break or wear but in my experience its allways pinion outer brg that wears first,who told you they didnt have brgs what did he think the diff run on,as pinion brgs wear it allows the crown wheel and pinion to become excessive