in my 1994 4x4 5.0 L- a clunking directly under my feet just started happening two days ago. i have NO idea what it is. it happens when im just driving down normal roads...theres no differences over bumps or in reverse, it clunks randomly at any time. temperature MIGHT have an effect...yesterday it was warm and it was clunking like crazy. this morning, it was a little chilly and it only clunked maybe 2 times when i was leaving the driveway and didnt do it again the whole drive. any ideas???

 

Could be numerous thangs from bushing on your radius arm need replacing to front driveshaft needs joints or is loose...

 

Read these captions:

 

i did try getting under there and moving the driveshaft back and fourth...wouldnt budge. bushings, come to think of it- i was told one was wearing out about a year ago...couldve just started causing problems i guess? but why is it so random? sometimes i get lots of clunking, sometimes none at all

 

You have to chock the wheels, set the e-brake, & shift to N before you can check the d'shaft. Even one as bad as this won't wiggle when the weight of the truck is trying to turn it against the stopped engine with a manual trans, or the park pawl in an automatic.