I have read through all of the typical vibration threads and none of them seem to apply. I feel vibrations in the entire vehicle that get more severe with an increase in speed. I purchased new tires and had them balanced already. I replaced the u-joints too and shocks too. I put it up on four jack stands and and the rear was fine. I put it into 4WD and found that the front right end started shaking once I got above 60 mph. Since I hear some very low humming from the front end at lower speeds, could it be that my front differential is shot? I have already replaced wheel bearings and am familiar with what that humming sounds like. Can someone tell me what the typical signals of a bad front differential would be? Thanks!

 

One thing you could do to check would be to put the truck up on jack stands in the front and check for play in the front driveshaft to differential, as well as where the cv shafts connect to the front axle housing. It could be that one of the outer bearings on the front axle has gone bad.

My bravada required the whole front diff to be rebuilt with new bearings soon after I purchased it, but I had different symptoms. My symptoms included a cyclical vibration at interstate speeds of 65-70mph with the vibration increasing in frequency and in intensity at speeds in excess of 70mph.

 

What did it cost to rebuilt your front diff?

 

Didn't cost me a dime. The dealership was required to fix any problem with the vehicle for the first 60days due to NYS Lemon Law warranty for vehicles under 75k miles.