Ive seen a zillon of half ton rear axles, ranging from very old to very modern with a ton of slop when pulling axle outward with the wheels off the ground. If there isn't any other obvious issue, noise, banging, whining, or excessive metal or chunks in the diff, run it. Some c-clip diffs just have this character. And you probably would of never known unless you pulled on the axle with wheels up. I also never can say ive seen any c-clips worn to replacement was necessary. But then again, ive havent seen it all.
