vibration/shudder

[harleydavidsonstroker]

hey guys im new here ive owned my 2006 f-350 for 4 years now and i love it best truck out there put over 70 000kms on it without any real issues till now. it has a 6 inch procomp lift since ive owned it and no rear problems till i upgraded the kit.

2 months ago i had the ford garage install new procomp traction bars on the back to take away the axle wrap on hard launches and they also installed new set of 8" procomp leafs in the rear, now it vibrates off the line worse then it did before but goes away once it hits 2 gear but on the highway it vibrates from 70 km/h to 110 km/h also, at highway speed it feels like a tire coming apart

its been to the ford garage 4 times since and they keep telling me the driveshaft is out of balance...i bought all new u joints i will be replacing these in the next few days hoping itll fix it but what do you guys think???

--------------------------------------------------------------------------------

[Snowbound]

Did they install the steady bearing drop spacers ?

[tonka250]

i had this same problem. do yourself a favor and unbolt the driveshaft from the truck.( let it hang) crawl under the truck and when u push up on the driveshaft there will be a hard spot, soft spot, hard spot... this sounds crazy but when u feel the soft spot stop and put the jack stand under to support the shaft. measure the distance between the factory spot and the carrier bearing. measure the front side and back side. the drive shaft carrier bearing is a an angle that needs to be copied on the drop bracket. go to your local metal shop or hardwear store and build a bracket out of 1/4" flat plate making sure you put the angle in it and this problem will go away for sure! i have a custom 10" lift on a 2006 f250 and had this problem and every off road shop around NC told me i couldnt get the vibration out... It doesnt have a hard shudder at all when taking off and i drove to the beach this weekend about 90mph with no vibration. if done right this will fix ur problem for sure.