ECGS diff bearing or CV axle

I ordered a East Coast Gear Supply diff bearing that is suppose to take care of a "wu wu wu" noise and some Vibrating. I spoke to ECGS and they said what I was experiencing was Very Common with Toyota trucks especially ones with lifts. My question now is how do I know without tearing apart if it's only that bearing or a bad cv axle. I've been driving on that bearing making noise for awhile....

 

I drove with the noise for over 10k miles. I had my mechanic do the swap to the bushing. He said the axle looked brand new and even showed me the bearing. The bearing looked fine to me and he agreed that it looked fine to him. I've read of people installing the bushing with axles that were showing wear who reported that they had no problems after installing the bushing - reinstalling the same axle.

 

Ok I was afraid I might be screwing stuff up. I don't understand it. Did you have the noise and vibration and this stopped it?!

 

As soon as I lifted the truck, the vibe started. Classic symptoms which stopped with 4wd engaged. I procrastinated on ordering the bushing for awhile, like all winter. Bought the tool from a member, then the bushing from ECGS. A couple months later had my mech do the install. As soon as it was installed, the sound and vibe were gone. Kinda wishing I would have just ordered a whole clamshell with the ARB locker, now that I have my compressor, though.