If you are only replacing the carrier bearings as you say, and have no need to remove the pinion, all you do is check backlash first, remove the carrier, replace the bearings, re install the carrier and re set the backlash to what it was before. Honestly f you want you can run a pattern afterwards, but if it is a used gearset and was quiet before, just reset the backlash and it should be the same. Used gearsets may have less to than perfect patterns.
