Car parts warehouse is just a local parts store. There not as big as AutoZone, orileys's, or advanced. But they aren't small time either. I agree, 4 months isn't long at all for a timken bearing. Ill bet it was just a bad part, it happens from time to time. Also, im sure you already know this, but both axle nut and bolt torque are critical for bearing life. Also knuckle cleanliness.