I have a 2005 ford 6.0 that makes a loud hollow thump sound like my muffler is dragging on the ground when I let off the throttle. It usually happens when I am on a long pull giving it a decent amount of throttle, and when I let off the throttle it makes the weird sound!!!! I also had the check engine light come on twice and the the third time it set it into limp mode. Has anybody had any expierience with this issue? Thanks for any help!

 

recently had the same issue on my little beast 5.8windsor gas.
she was running fine... but when i let of i got a single knock. eventually...it turned into multiple knocks...and evolved to a definite crank speed knock. ended up being a rod bearing that had chewed into the journal enough that the #1 piston was slamming into the counterweight on the crank on the downstroke at bdc. new crank, new bearings, new seals... ran like a new engine. gotta catch it soon enough tho.

also... maybe ujoint? kiss keep it simple silly
get under the truck and grab ahold of your driveshaft... if you can move it around and it has play in it... you probably need to replace them.

 

You need to pull the codes. I am willing to bet the noise you heard was what we call a turbo fart. I am also willing to bet that the CEL is for the turbo over boost/under boost code P0299 I believe. I would also be willing to bet that your veins are stuck causing this issue. If you are able to get the codes read start there, if not take it to a trusted dealer or independant that is familiar with the 6.0 and get it fixed. Running that truck with a stuck turbo will lift your heads, if they havent been already.

Ypu cn rest assured that if your diesel truck was knocking from a rod or crank issue you would know it. The bottom end on the 6.0's are pretty stout.

Good Luck,

Sarge

 

Gonna send this one down to the 6.0L forum...

 

Sarge has you off to a great start follow his lead

Post any DTC you find when scanned