not sure why ppl telling you it's the carrier bearings ???
if your pinion shaft moves in and out a quarter inch then it's the pinion bearings that are shot and the crush sleeve to also ur pinion may have chewed on the carrier it's self i had two diffs do that to me!
recomend full rebuild cuz gears will be shot to almost certan !! and install crush sleeve eliminator kits from allprooffroad.com harder to set up but when done right bom proof !!! espesialy with lockers and lower gears + bigger tires i have done it all and gears are good even though i break axle's and stripped my detriot locker recently gears and pinion are good just need new locker now and bom prof axles hope this helps fell free to contact me for help!!!
shannon 84toymonster