OK folks, help me diagnois an issue that popped up in the past week. I've got a 00 Ranger, 3.0L, 5 Spd, short bed, 95K miles. I'm starting to get a squeal from the rear end area under these conditions: trans must be in gear, must have foot giving it gas, less than 25mph. It's then that I get what sounds to me like a bad wheel bearing sound. I've tried to do a bunch of things: get up to speed and put into neutral- squeal goes away. Keep it in gear but let my foot off gas- squeal goes away-- if I put foot back on gas, squeal comes back. Over 25-30mph, I don't hear it. So it seems to be to be related to the drive train, and when there is torque on the drive train up to ~~25mph.

I tend to not think wheel bearing seeing it's almost like when the drive train is under strain (on the gas) is when the noise is there. If it was a bearing, then it should be there all the time, at any speed. It's kind of hard to determine exactly where the issue is while driving the car w/ me leaning out the door and trying to 'see' where the sound is coming from. I'm pretty sure though that it seems to be from the back end of the drive train. I can put it up on jack stands but just trying to narrow down some things first. Have you guys run into something like this before? Can this be the rear end going?? (It's not grinding or any hesitation or jerkyness from the rear end though)

Thoughts?

 

Possibly a pinion bearing, or a binding U-joint.
And no, bearings don't necessarily make noises at all speeds. I had a bad pinion bearing in my work car and it started out just making noise between 45-55 mph. It did get progressively worse, by the time it was finally fixed, it would make noise at any speed over 20 mph.
Jack up the rear, have somebody run it in gear while you try to listen at different locations. Just don't run it over 30-35 mph on the speedo. I've used a tube (PVC pipe) as a stethescope to help. That way you can stay to the side and not go under the vehicle!
This is potentially very dangerous. Use extreme care, use a helper, and point the truck in a safe direction in case it comes off the stands/ jack and takes off before your helper can react and slam on the brakes.
Location of the noise should steer you in the right direction.

 

BA dawg has a good idea. It could be the gears themselves making the noise. If it is the gears worn, the noise might not be there when there is no load on them. If it is the gears, they should go a long time before you will have to do something.. While you have it jacked up, I would change the oil in the differential and pay attention to weather there are any filings in the old oil. I don't know what the laws are in your area, but you could ride in the back, right over the differential, and listen while someone else drives. That way the pinion bearing would be under a load. I would try to find an area with light traffic and a very smooth road to cut down on road noise.