I've been enjoying my 98' Taco v6 4x4 since the day I brought it home. Recently I took it up to the mountians and had some fun logging roads, mud, small hill climbs etc.

Not too long after that trip I noticed a strange humming/whining noise comming from the engine. I dont really start to hear it until I rev the engine between 1000 and 1200 rpms. The noise either goes away or is drowned out by the engine noise by 2000 rpms. I've checked the belts and they don't look damaged. The Power steering fluid is at the correct level and there are no leaks. My truck still functions fine but this noise is really begining to annoy me, especially in parking lots when I hear it the most.
I'm trying to pinpoint what might be causing the noise. Any idea's or suggestions would help a lot.

Bearing in oneof your pulleys maybe. If so before you break down and hit the dealer some of those bearings only come w/ the pulley not seperately. I found a place here I can buy the sealed bearings and its mucho cheaper that way.