Heres the deal. I went ahead and had my 4.88's installed, while waiting on my Rize kit to be delivered. '07 fx4 screw.

Took my buddy for a ride a couple weeks later and showed him the new found torque.

I floored it and got ALOT of bad wheelhop. Now driving betwen 35 & 40, 65 & up, I get a bad vibration in the rear.

It looks like the middle leaf spring moved foward about 1/8 to 1/4.

Could this cause that much of a wheel vibration?

I need to fix this problem before the Rize goes on in a couple weeks.

 

i dont know much about gears at all, but don't gears have a break in period? it sounds like you had them installed by a shop, can't hurt to bring your truck their and just have them look it over to double check everything.

 

It wasnt the gears that caused the problem. Ive been driving with them installed for a couple weeks now. Prob clocked over 900 miles.

The problem occured after the "wheelhop".

I did a burnout then the tire grabbed and made a bad wheelhop. I think something shifted.

 

in order for your leaf spring to move forward like that both center pins through the spring pack would need to break, in which case your rear axle would be crooked under the truck, id get that checked out asap.

 

yea, thats true. i didn't even think about the 2 pins going into the leafs. i would guess its something with gears. if it was leaf's shifting, it would be really obvious.

 

Took it to ford. Messed up driveshaft some how.

Warranty repair. Problem fixed.

Rize 8in, soon to follow.