Mine fixed itself. Check the rear diff and see how low it is. If it's low, refill it and wait.
Get outta town! Seriously?!? It's my experience that issues don't fix themselves.
Well 2 things can happen: your rear brakes may fail due to all the oil leakage onto the drum/hardware and your rear diff will run low on oil and cause premature wear to your gears/differential.
If you have a tundra brake upgrade, the 1st issue may not be a huge concern. As for the diff running low, just keep refilling it. Not sure what affect the oil has on the wheel bearing though.
I'm not recommending EITHER of these as both are dangerous situations.
I will check (as soon as I figure out how) but yeah I'm sure it's not helping the braking back there. I haven't noticed a big decrease in braking performance yet so I guess that is a good thing.