i have a 3 inch lift with 35s.ok so while im driving im hearing a high pitch whistle. like a tea pot whistle. it only does it while im in gear. just replaced the rear drive shaft. the front drive shaft seems to be ok. it was slinging some grease, but it seems to be ok.the boot isnt torn. i have no idea what this noise is. throw out bearing?

 

Try slightly applying pressure to the clutch pedal and see if it goes away

 

yea it usually goes away when i push the clutch in.
i have a feeling its that throw out bearing.