Thunking DRIVIN ME NUTS!!!

I checked it and the frame rail is actually a millimeter above the frame on the passenger side and on the frame on the driver side.

I will be having a bushing weekend. I am swapping the sway bar bushings, body mount bushings, and possibly leaf spring shackle bushings.

Fingers crossed.

 

Wow that is a pretty violent thud! Im gonna watch it again for more ideas.

Ok so I had a reply typed out on my iPad and it died ugh... haha

Seems to me when watching it that it sounds like a "light" clunk like something hitting a lighter thinner metal. Not a deep hard THUNK like a solid piece of metal. (could be totally wrong here)

anything on the exhaust moving around hitting the bed? Is a hanger broke? or one of the rubber hangers missing or torn?

Or like Trooper mentioned the u-joint, but I'd think there would be more witness marks on the skid or u-joint it self. Try taking the tank skid off and see if the noise goes away?

It also seems like the clunk happens twice, once when the suspension compresses and hits "said culprit" and then again when the suspension un compresses and passes "said culprit" again.

Jumping in the bed doesn't produce anything? How about shaking the crap out of the bed? both while standing in it and out side of it. Grab a corner and shake the crap out of it? anything? IMO something is making contact somewhere and should be showing signs of it.

Good luck and keep us updated with what you find!

 

I agree on the sound. The body mounts are my main suspect right now. Granted that there have been many suspects so far. New body mounts come in this weekend. The exhaust is tight and not interfering. I just sold my canopy so I can try jumping. Couldn't reproduce by moving the bed by hand. Will keep you guys updated.

 

Have you checked your fuel filler hoses? Can you think back to what you may have done to your truck before this problem happened? also in the video it seems the noise happens after the front recoils from the bump,just before the rear hits.did you maybe leave any tools up on the frame rail or flat areas? your not missing a small sledge hammer are you? Good luck with your issue. Im sure you'll find the noise. When you do, Im sure there wont be any nice words heard for miles around.

 

Well, I did lift the truck with a jack and dropped it a few times. The sound is definitely coming from the rear. Funny you mention the tools left in the undercarriage though. I founf my old craftsman clench wrench on a differential bolt. Not the cause, but funny. What would I be looking for in the fuel lines?

 

check the filler neck from the gas tank to the area where you fill the tank.if its loose it could be hitting the frame, or something around it.

 

I actually found it!!! I was going to swap my leaf shackle bushings when I noticed something. I took the wheel off and started jacking tbe axle back ...."TWANG"! The lower shackle mount was binding really bad. I was going to change it but the OME bushings are smaller than stock and apparently no shop can sell bushings by size..... Grumble grumble.... But, I greased up the bushing and the thunking is GONE! Thanks everyone for your help on this.

 

Ummmm dude... page 3 POST 53# & your welcome......

 

Wow amazing you found it! Well at least you know what it is now and don't have to go nuts any more!