I have a 1998 f150 4x4 lariat. about 130k miles.U-joint has never been replaced. the truck has recently started making a fluttering sound from the rear end underneath the truck. it sounds like a damn tweety bird is stuck under there. anyways the problem only happens ON THROTTLE and not while coasting. also there is a clicking coming from seemingly the same area underneath the truck (sounds like somewhere near the drive shaft). i have not gotten the chance to jack the truck up and see if i could reproduce the problem. also i should say that while idling with the truck in drive and foot OFF the brake there is squeaking on about every turn of the drive shaf. if youve ever had the same problem please let me know how you got it fixed. any suggestions are appreciated! thanks.

 

If it is a bad u-joint (which it sounds like) the only way to repair is replace it. Before the driveshaft drops on the road. Would not hurt to replace the front u-joint also.

 

Yes that's exactly what it was. I broke down and took it to a mechanic because i did not have time to do the work myself. Turns out it was the u joint. Thanks for the help