extremely loud clunking noise

[onefast3g]

Ok i am new here but have done a million searches trying to figure this out and no dice. I have a e99 7.3 5-speed manual 4x4 with manual locking front hubs 129,000 miles. the other night i was driving home and heard a clunking almost like someone was banging on the floor. as i would accelerate it would get fast and was very consistant, but when i would let off the gas it would stop or become real faint. clunk......clunk.......clunk.. clunk clunk clunk clunk... at 55 it sounds like someone has a air hammer an is hitting the floor i can feel it in the shifter and in the 4wd shifter. any help would be appreciated thanks greg

[Joel]

I really feel like I had this issue before, but i canr remember what it was.

how are the steering knuckles?
If you lock the hubs but leave the transfer case unlocked is there any difference?
If you leave the hubs unlocked but engage the transfer case?
wheel bearings ever done?

[onefast3g]

as far as i know the bearing have been replaced. not sure about the rest. the noise is so loud you can hear it echo of other cars and even houses.

[onefast3g]

o and it can be in 4wd 2wd the front hubs locked and in 2 or 4 nothing changes

[aflores]

this sounds similar to my issue, except mine only make the noise when im off the throttle. when im on the throttle it doesn't make a sound. still haven't found the issue but i know its not the transmission and its not the rear end. Im gonna take apart the tcase this weekend.

ill let you know what it is if find out

[harman99stroker]

make sure your axle joints aront hitting the lower balljoint stud ...im fixing that problem in mine right not the is a axle shaft bearing in the back of your wheel bearing that wears out and lets the axle move enough to let it slap off that stud....easy to see if thats the problem there will be marks on the ujoint caps and yokes

[aflores]

Check your transfer case. Mine ended up having a worn shift fork causing the problem