vibration/shudder

[6.0bcstroker]

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???

[wngnt954]

Check the pinion angle. I have a nasty driveline vibration from about 60 mph when I lay into it and my lift blocks don't taper enough. So shims are going in next week.


Sent from my Autoguide iPhone app

[V8Ranger]

6.0bcstroker:
Did you have any resolution to your problem? I have a customer with a 6-8" lifted 06 f-350 6.0 and has a bad shudder off the line, very bad when towing, we shimmed the driveshaft at the steady bearing and shimmed the springs to help the pinion, angles are almost the same as my 05' f-350 6.0 6" lift. He has also installed ladder bars to eliminate the shudder, but seems to be making it worse. His truck has brand new u-joints, steady bearing, balanced shafts. new firestone airbags to maintain ride height when loaded. Just wondering what you found with yours and maybe I can apply it to this truck!
Thanx,
V8Ranger

[V8Ranger]

So we started again by removing the ladder bars that are supposed to limit axle wrap, made it better with them off. dropped pressure in air bags to 0, made it better again but not acceptable. cranked pressure on bags up to 70 psi, vibration horrible. Came down to the 4/1 lift spring being too weak for the torque and load being pulled. removed lift springs, install 5/1 extra heavy duty springs, very slight vibration, left the ladder bars off. customer is very happy with results, even pulling his bobcat trailer!! vibrates less than my stock 05-f350!!!
V8ranger