8.75 Diff Questions 2nd try

sounds like to me you need to pull it apart an take a look ... axles must come out those bearing can be hard to see ..if ok put some grease in them before installing ...keeps them from running dry till gear lube gets there ... the center section only three bearing's in it the pinion bearing is preloaded so there should be no side to side or up an down movement first off .. the rest just ck the wear pattern ...... there a good book on these at barns an noble there pretty simple ... the 489 has 1 7/8 pinion shaft stout most look after the 741 shaft is dont quote me on this 1 1/8 light weight or its around 1 1/2 have to look them up again any how there fairly easy .... wish you luck