daily driver 2000 durango 4x4 4.7 developed a weird noise sounds like drive shaft is hitting something the sound comes an goes but does it half the time im driving..i replaced u joint no marks on drive shaft where it mightve been rubbing on..ive had no problems out of it i replaced a speed sensor right before this started happening ..i havent checked the front driveshaft yet ..nothing seems loose or visible ..any suggestions opinons?

 

http://www.ehow.com/how_5491346_chec...-bearings.html

I would suggest checking the wheel bearings next.