ok first thing is i have a 99 f150 4x4 with 4.6 with around 96k on it. well it just started tonight when im going id say between 20 and 30 mph and i tap the gas i get a clunk and when i let off the gas i get a clunk you can hear it and feel it. now i replaced my rearend about 6 months ago with one from a boneyard as i had broke the carrier in half in my old one pulling into my driveway. also this has been bothering me for awhile now when i drive between say 60 and 75 it get a pretty bad viberation but like 1 second after i let off the gas it goes away? totally puzzling to me cause im still going just as fast and everything is spinning but no vibes. and two more questions. if i excelerate hard i get a clunk clunk clunk clunk noise from the rear end. and finally when backing up mainly i think or maybe even going slow in drive i get a squeak squeak squeak but it goes away after i get to about 20 mph.... please anyone with any answers or thoughts to my problems please help. i listed them all in hopes that maybe some or all of them are related. oh yeah also i get that little studder step inbetween 1st and second gear. i need to get it fixed soon and im really strapped on time working 7 days a week and going to school so any help as to where i could start looking or what to start replacing would be grately appreciated.
thanks
jesse

 

Check your U-Joints... that's what it sounds like to me. Do it quickly, I might add, since given the symptoms, it sounds like at least one of them could be severely worn, and if it gives up, you could be in serious trouble.

 

Maybe a trans mount?

 

i took the drive shaft out tonight and the rear u joint where it goes into the drive shaft part had a big chunk missing out of the ring and is kinda flared out. not sure how it happened but it looks like its been that way for awhile. i got school tommorrow night so wednesday its off to the bone yard for a new ds.
thanks for the help

ill let you guys know if it helps