High speed, rearward vibration.

Hey guys, I'm looking for some advice or help on where I need to go from here to find this vibration and eliminate it. I have a skyjacker 3'' lift, which included shocks, front and rear as well as rear springs. I installed a diff drop for upfront and a new carrier/center bearing. My guess is either, rear wheel bearing, rear diff bearing, or a wheel balance(which I find hard to be since I balance and rotate bi-annually).

Symptom: Speeds higher than 40mph start to rock the truck moreso than low speeds. The higher the speed the more fast the rocking, which would indicate something rotational/driveline'ish. It feels more in my back than my feet, but the entire truck definitely vibes. If I press the gas to down shift and accelerate the vibrations will subside sometimes until the revs come back down. Most of the vibrations are severe and the truck rock/shake is noticable from the outside of the truck on the highway, and sometimes they just disappear for a few minutes. I have been in traffic and literally seen the truck lifting a side as if it were driving on an oval tire driving at sub 20mph. It's not a couple inches of rocking, but something both passengers can notice and feel and see in all limbs.

I know there are a TON of vibration threads out there, I feel like I've searched and read them all. Hoping someone has had the exact same experience as mine to point me in the right direction since everything else I've replaced or installed hasn't helped.

 

I have a similar vibration and seeking the same type of answer.

 

anyone get help? I have a toytec lift and have major vibes after 70+ mph

 

I don't know anything about driveline vibrations but that sounds more severe than a driveshaft could cause. Check your rear tires, you may have separated a belt on one or something.

 

Did you solve your problem?
I got a Tom Woods Driveshaft. Ot sort of solved most of my problems. But a new one is High speed vibes