Diff noise vs wheel bearing noise

All -

I've got a '98 4Runner that makes a growl that changes with vehicle speed. I've taken it to a shop for some other work (that I probably should have done myself) and they diagnosed the sound as rear wheel bearings.

Before I buy parts and tear it apart how can I confirm that the noise is wheel bearings and not the diff?

Thanks

 

Jack up the rear end, put in neutral, and spin the wheels. You also shouldnt have any in/out play in the wheel.

 

Is it your thought that I'll be able to hear the noise when spinning the wheels by hand?

 

if they are extremely bad you prob will be able to hear or feel it in the tire.

 

Those rear axle bearings are normally very durable. Are they original? How many miles on them?

I've only seen rear axle bearings on 1st gens Tacomas go bad when the seal fails. A tell-tale for this is gear oil getting to the drum brakes and then being flung onto the inside of the tire. Have the brake drums been pulled to inspect for gear oil leaks?

I think the rear diff is a more likely suspect for your noise. Does the sound/rumble change pitch when you first let off the gas. Between accelerating and decelerating?

 

I am personally one my third set of bearings in 100k miles, granted I have always gone name brand aftermarket, not Toyota. I have also replaced the wheel seals twice. First time I improperly installed which led to the bearings becoming saturated and gummy.

I should of clarified, you should be able to hear a noise. can also check for pinion play when its in the air and in neutral.

 

I appreciate the replies. I asked the shop to diagnose the noise, but not fix. They said the noise is rear wheel bearings. (You know all this already). After talking to y'all and checking on the DIY part of the job and seeing that it was going to probably have a disabled truck in my garage for better than a week (with me working on the truck on weekends, and for The Man during the week) I decided to ask them how much. They quoted me $610. So, they have the gig. Now, if the noise doesn't get fixed after changing wheel bearings we'll have another conversation. But, I thought that was a reasonable price.