Agreed on packing the axle with grease--this will help seal the bearings which are not sealed (just shielded) and not waterproof. In fact, grease should be smeared on bolt sides of the ball bearings if you plan on driving in deep water (axles submerged) or mud.
You need to keep the diff open and you push on the pinion at the same time you tight the drive shaf tand you gonna have less wiggle i have do it on mine and it work very well no wiggle and no binding
So sometimes the driveshafts can be offset in that case you would disassemble and turn one half 180° and reassemble the goal is to find a happy smooth location
