Weird Sound i need help.

[Vinaell]

Ok im going to try to be as descriptive as i can. First off the sound comes from underneath it happens when my Rpms drop lower then about 1300 so usually when im slowing down in any gear. But its a sound like ziiiinnnnngg like a nut spinning really fast on a bolt. but if i keep my rpms over 1500 or shift to neautral to stop. And the weird part is it that it happens after driving for awhile. it wont happen if i drive to the store. I have to be driving for awhile before it starts happpening

 

[deweyville65]

Check the fluid level in the transmission

 

[Vinaell]

Checked it and its good.

 

[1992fordgreen]

Usually those no good noises end up being the transfer case...slight chance it could be the culprit...or are you just hearing a lousy servo motor?

 

[morgfarm1]

Well, if the descriptor to the left is right, I'm going to agree with 1992FordGreen. Probably to do with the transfercase/drivetrain in some way. Engines don't make that noise, but transmissions will.
Try flushing the trans fluid and putting in a new tranny filter? It could be clogged and keeping fluid from getting into the transfercases or torque converters. I'm no ace mechanic, but are worth a shot.