front hub is shot after 9 months OTR?

Back in September I had to do my ball joints. While my OEM hubs had no problems, I figured with ~100k miles it would be good preventative maintenance to do those and the u-joints while I had the jeep up (doh).

I made sure to get the Timkens from autozone, and I rented a 250lb. torque wrench from pep boys to make sure I got the preload right.

Now I'm lazy and have my hands full with my sound deadening - haven't even had a chance to change my oil .. so I haven't jacked it up and wiggled things around yet - however, I'm getting a constant pitch "wumwumwum" that speeds up with vehicle speed. Sounds a bit like loud tire tread, except of course that it doesn't matter what I'm, driving on.

I timed it, and it cycles at wheel speed (approx. 10x the mph), so it's probably not the TC output bearing, which was my initial thought, since I drove it to NY dry last summer.

So operating under the assumption that it is the wheel bearing, why the heck did it fail so soon, and what should I do to not have this happen again? I should still have the receipt, but do I really want another Timken? Is there anything other than preload (like other worn or mis-tightened parts) that could cause a wheel bearing to prematurely fail?

I have had issues with my hubs as well. I replaced both within weeks of each other and the right side went to gowling and grinding in about 1000 miles. I replaced it again and within 500 miles the left began to roar. At that point I decided to re-torque the left since I had nothing to lose. After re-torquing the hub the symptoms ended, so I re-torqued the right side. To torque these I used a 3/4" drive breaker bar with a cheater pipe that extended the bar 24". I can not say that this is a fix to your problem, but I figured that my hubs may not have been pressed correctly at the assembly line and the additional stress caused them to seat. I was able to move the hub nut almost 1/4 turn when I torqued them the second time. Now I have put about 1300 miles on the XJ with no other hub bearing problems.

Jwalkman

I had almost the same thing going on, when I installed my Federal Mogul hubs. I torqued to spec and felt something slip, I figured the spacing on the bearings wasn't just right and they seated when I torqued the whole thing together. I then tried to spin it by hand and it turned pretty stiff. I backed the nut off and retorqued to 25 ft pounds under spec. It spun fairly free, at least free enough that it would likely wear in without overheating.
I actually ran the bearing for a few miles, jacked up the front and checked if the bearing seemed to be tightening back up again, from heat expansion.
I made my mistakes with too tight bearings in my early years. They expand with the heat and self destruct pretty quick, without enough play to expand some. I always have .003 (.001-.003) in the back of my mind when messing with most any bearing, it seems to be near ideal play in many cases. A little loose is probably better than too tight. At the very least, a bearing should turn without much noticable excess drag cold and hot.
Most replacement hubs from a reputable manufacturer come with a guarantee. Mine stipulated that the faulty hub had to be returned in the original box, I guess so they could scan the bar codes and such.