Ford Repair: Whining noise, wheel bearings, wheel bearing

Question
I have a 1988 truck with 250,000 miles.  Recently it started making a whinIing noise from the rear end or driver side back wheel.  I am not sure where is coming from but it gets louder the faster I drive.  When I led off the gas it quiets down but you can still hear it.  This problem started about the same time when my truck would lock up after being parked for a while. Battery would be down so I would put it on neutral to let it roll down hill but it would not move.  I had to rock it until something would pop, then it would roll.  I do not know for sure if this was the cause.  I took the cover of the rear end to check for broken parts inside the rear, but could not see anything that was obvious.  I change the DIRTY rearend oil, but still makes the same whining noise (loud when driving).  I stop driving my truck b/c I was afraid that it would burn something up/brake.  What do you thing it might be, thanks!!!

Answer
Alfred, the first thing that I would do is lift that side of the truck up and check to see if the wheel bearing is going out.  One way to do this is to place one hand on the top of the wheel, and the other on the bottom.  Then "rock" the wheel back and forth.  If there is a lot of play, then odds are that the bearings are going out.  If there is not any play, then you will need to remove the wheel and the brake drum to check the brake shoes.  Look for metal to metal contact between the brake shoes and the brake drum.  Then, take off the dust cover on the axle and look at the wheel bearings.  If the grease looks like it has been baked, then it is time for new bearings.  I hope this helps,    Jason