Vibration between 20 and 30mph

I have 2011 reg cab 4x4, 3"lift spacer and blocks 265 75 16 bfg's and after putting on the lift i seem to have slight vibration at low speeds. any ideas?

 

Is it like a humming feeling, and it goes away when you shift into 4WD?

 

no humming noise, just feel it in the steering wheel a little, i havent tryed in 4x4 yet to see if it goes away. I did a dif drop on it as well, anychance that would cause issues?

 

I lifted my 09 with the the same lift set up and had the same vibration. very lite vibration most people cant even notice it. I tried everything and finaly decided to live with it. i was told by 4wheel parts that it wouldn't hurt anything.

 

I too have nearly the exactly same scenario; except, mine occurse just before the shift to second at about 10MPH.

I've read briefly that this is a relatively normal occurrence. The general consensus seems to be the angle of the final drive shaft to the rear diff. Haven't found a fix for it yet, other than dropping the drive shaft a bit.

2 things, 1) the front dif drop shouldn't have anything to do with it as this only occurs in 2WD. 2) I was hoping a rear block lift would have stopped it. I have an AAL lift. I see you have a block lift. Block lifts generally are triangular shaped to align the drive shaft; assuming your rear block is triangular.

Love to see the responses on this topic.

 

Try putting it in 4WD when you feel the vibe, it will most likely go away. Many lifted 4x4's have that problem, incl. myself. Some have had their dealers replace the front diff. The vibe disappeared, but came back shortly thereafter in all cases I know about. It's a bearing in the front diff.
My vibe showed up right after I put 5100's in at 1.75". I have finally decided to ignore it. One dealer can't feel it, the other one says it's the lift (he is right). It's been there now for 30K miles or so, and has stayed the same: does not get better nor worse.

Let us know if yours goes away when you switch into 4WD. There is a loooong thead about it over on TN. Search for "Help identifying noise/feeling" as the subject.

 

I think this is the reason why it IS the front diff. It does not happen to 2WD trucks, at least not the vibe I am (and most are) talking about. But it's not the diff drop (as you said), more likely the drive shaft angle.

BTW, some people have successfully replaced only that front diff bearing for a few bucks, but a lot of work. I think the vibe came back later for them also as long as the lift stayed on.