I recently came across some topics about frame beaming and from what I've read, it describes the exact symptoms for the issue I've had with my truck since purchased brand new almost 5yrs ago (2007 Silverado 1500 LS crew cab 46K miles). I've taken it back to dealer about 4 times and I stopped trying to get this fixed after fourth time as it's always an inconvenience having to give up transportation for a day or two and instead I tried getting used to the vibration but it's very annoying and embarrasing at times when I have collegues riding with me. So far the chevy dealer has offered no real fix or nothing that even rhymes with "frame beaming" has ever been mentioned to me by the service reps/techs. Just a simple tire rotation, balancing, alingment, etc... is all they've done. Now I'm trying to find out as much as I can regarding this issue or anyone that may have some useful feedback, a solution or fix for this issue. Thanks!