Sounds like you have a four-wheel-drive and the half shaft wasn't installed or the axle nut wasn't torqued properly. The outer cv joint is what holds the bearing assembly together. There must never be any vehicle weight on the bearing unless that cv joint is torqued to specs. Specs can be very high. Almost all cars call for around 180 foot pounds. Some GM trucks call for up to 240 foot pounds. The value is usually listed on the sheet that comes with the bearing. That has to be set with a click-type torque wrench. If the axle nut isn't torqued to specs, the most common symptom is the bearing becomes noisy and makes a loud humming sound.
Also, many vehicles use a "torque-to-yield axle nut which is a one-time-use nut. It must be replaced, not reused, anytime it is loosened. If you have that design, a new nut typically comes with the new bearing. Reusing the old nut won't cause what you described. It will cause problems later.
Those bearings are really tough. I've never seen one on any brand of vehicle be defective out of the box. All failures are due to improper installation procedures.
Wednesday, February 17th, 2016 AT 3:27 PM