Pinion Bearing

Since I've been running this Ox Locker, its seems I've been stressing the front-end. I now have a little play in what appears to be the rear pinion bearing. Can I get away with just replacing the rear pinion bearing. I tried cranking down on the pinion nut, with no luck. Its like I lost the preload on the bearing? but that still would not explain the movement?

is the movement rotational, in and out, or side to side? You can try replacing the pinion bearing, and see where it gets you. You may need to do some pinion shimming if that doesn't get the preload you need.

Vertical

The movement is vertical.

Vertical but not horizontal?

What axle are we talking about here? Not sure if you run stock diffs or something you swapped in.

if you've spun a bearing, yes you will loose the preload.

you may have torn shims off too.

at any rate, pull the pinion and re-install NEW shims of the exact thickness as the old ones, new bearings, reinstall and recheck preload (without the carrier installed) and then check for pattern.

you can post pictures of your pattern here if you want.