2005 Yukon (5.3) vibration question

[fishmaycraft]

My wife's Yukon has started vibrating while maintaining speed around 55 mph. If you accelerate it goes away, and if you let off the accelerator it goes away. I thought it might be an overdrive transmission problem, however I noticed it doing it some while in tow-haul mode also (both while towing and not towing).

A little wishful thinking here but do you think unbalanced or non-round rear tires could be the cause? We put a cheap set on last year in an attempt to make it until all 4 needed to be replaced but the rears are already about worn out (especially the rear passenger side), and I thought that tire used to have a weight on it but there isn't one now.

Thanks for the help!

FMC

 

[offerman73]

My Tahoe had the same issue and the first thing I'd look into would be u joints. They are fairly cheap and if they've never or seldemly been greased they are more prone to failure. The worst scenario would be the rearend is starting to get "loose" which would be a bit more costly. You could block the wheels, put the truck in neutral and twist and wiggle the front and rear driveshafts to see if there is play in the u joints. If the ujoints don't turn out to be the problem than you might need to look elsewhere such as differentials or even the transfercase if it's a 4x4. I was experiencing a compound of bad ujoints and a rear differential on its last leg.

 

[offerman73]

As far as tires go, I wouldn't think they'd give you an intermittent vibration. Just my opinion. How many miles does the truck have? Is it 2wd or 4wd? Might help pinpoint the problem.