Hey all, Ive got a Roush charged 06 that has a vibration while accelerating from about 5 to 20 mph. Does it really bad while towing. Ive recently been told (by Ford) that it is probably due to torque on the rear axel and it is causing pinion chatter. I was also told that a ladder bar could help the situation but arent ladder bars for lifted trucks? Mine is lowered 3 inches in the rear. What do you all think. Ladder bars or is there someting else I should be looking at? I know enough about rear suspension to get myself in trouble.. not enough to understand it all. I know the bars will limit wheel hop, but wil they help me??? Thanks for all your help.
Scott

 

Can you lower 3" and not change the pinion angle or driveshaft length, and not get some type of vibration or noise?

 

Obviously not, thats why Im looking for ideas on how to fix it.... ???

 

Is it worse under hard throttle? Could be the tranny.

 

Not that I can notice. Under an average acceleration is when you feel it most. And like I said, towing really does it. Actually bounces the winshield wipers on the glass.

 

what did you do to lower the rear 3"?

did you change the axle angle at all when you lowered it?

 

Ford had installed 3" lowering shackles and 2" lowering springs to the truck while for sale on the lot. I saw it, added some other things and bought it.

 

U-joints good???

 

I would assume. Truck has 22k on it, has done it since day one.

 

I had the belltech shackles on the back of my 04 that lowered it 2", and it vibrated from 5-20 really bad under acceleration. Ended up that when the shackles were installed, they didn't install shims like they were supposed to to get the angles back in line. After getting them put in, the vibration was gone.

 

Sounds like the pinion angle needs to be corrected sight unseen.