The front crush sleeve has already been set, just torque the pinion nuts to 165-180 ft-lbs. & they will be fine.
recommend against u-bolts there. Or at least be careful to not overtighten the nuts even slightly. It is just too easy to overtighten them which can easily ruin the u-joint. Not even the winner of the last two year's EMC at the King of the Hammers was running u-bolts there.