vibration after installing leveling kit

I just installed a 2.5 in. leveling kit on my 2010 tacoma, very simple, no problems. As soon as I test drove it I noticed a rhythmic vibration up front, more noticeable between 30 and 45 mph. So i jacked it up and spun the tires and noticed when i spun the left front, the front diff had the same sound and rhythem of vibration. what could have changed so much to cause this? I have not heard of anyone having the same problems. What should i do?

 

ECGS bushing. Welcome to TW.
http://eastcoastgearsupply.com/i-8536125-toyota-8-clamshell-bushing.html

 

Lot of people have had this problem.

 

thanks man, that link gave me a better understanding of whats going on with the front diff vibration.