Once backlash is set then you’ll add shims for proper preload. The exact amount is determined by the axle you’re assembling; for a Dana 44, about 0.015-0.0075 per side. Wrestling the ARB Air Locker with the shims external of the carrier bearings is a three-hand magic trick. The shims, some paper-thin, must be gently installed and not wrinkled as the locker and bearings are tapped in place with a rubber mallet. Persistence and care pay off, but muttered four-letter words are not uncommon, especially from the first-time gear apprentice.