Box sound's and drives fine with no crunching or whining ect...except when,for example:

Driving along comming up to junction so changed down to 2nd,release clutch and as the rev's drop down when they get to about 1.5-2k there is a terrible transmission noise.Sure its the gearbox sounds really loud and high pitched
So,ive been told its the diff bearings are worn and need a new box.Right or wrong?

Just in case it could be something else rather than change the box and still have this problem

Thanks

 

Come on guys someone must have an opinion.On the second page with not 1 answer