high speed vibration, input needed

[t.stimpson]

my 09 yukon xl denali has a high speed vibration around 75 mph and its mostly there all the time but is inconsistent and sometimes disappears. It has 108K and I recently replaced all the shocks, lower ball joints, both front hubs, complete front brake overhaul with new rotors and the D/S front cv axle. I only replaced one axle as it had a torn boot. The tires are pretty new and had them rebalanced just recently though I will probably have them done again as weights can fall off. But I'm trying to think of what else might cause this. Intermittent makes me think its a bearing, or am I wrong? I guess the next step would be to replace both driveshaft u joints. The vibration seems to be coming from the front end, can kinda feel it in the steering wheel and the floor. I guess it would be a good idea to replace the other cv axle as well? It almost feels like a hub bearing but they are new and I jacked it up again the other day and no movement when trying to move the tire. No funny sounds either when rolling the tire. Any input would be appreciated.

 

[08grey]

Motor mount?

 

[t.stimpson]

how would a motor mount cause this? Ive heard there are issues with them on these models.

 

[ccapehartusarmyINF.(ret)]

its not a bearing bearings have a loud and terrible noises at low speeds
you can check the motor mounts put it in gear while holding the brakes give it some gas in both drive and reverse and if the engine moves excessively its a good sign the motor mounts mite be bad

 

[AZSCTACO]

IMO it could just be the roads you are driving on. Mine has intermittent vibrations as well near those speeds. I noticed it more on certain highways around town here. The roads have high/low spots that I'm assuming is caused by a combination of the Arizona heat, the rubberizing compound they put down, and heavy trucks.

I just recently had 3 of my 4 tires start to have tread separation. That also may be causing the issue, but it highly unlikely. It's hard to tell from just looking at them. The shop would have to put them on a roadforce balancing machine in order to tell. Good luck....I know it used to drive me crazy.

 

[TowGMC]

First place to start is balancing the tires. But watch them do the balance. Just because they get the machine to read all "zeros" doesn't mean it's round. I've seen horribly out of round tires "balanced" so it reads all zeros but the tire is still going to hop down the road. In the tire business they say they could balance an egg but it'll still go down the road like an egg. The best way to check the wheel/ tire combo is on a Hunter RF9700 Road Force machine, assuming the tech knows what they're doing.

If that checks out, then it's time to dig deeper. Is the drive shaft balanced?

 

[08grey]

Road force will balance a egg also.

 

[tgui]

I have this prob, did you find a fix?

 

[sumo]

Road force will balance a egg also.

Have you tried a tire rotation and does ignore still happen after? My 17 set of rims and tires had this problem. When one rim was on the front, it would vibrate so bad at 70 mph you cold feel it in your teeth lol.
Even though all tires balanced one rim and tire run out was bad. Road force balanced fixed that problem. What it does is measures the rim run out and tire stiffness. When it done it tells you a spot on the rim and tire. You dismount the tire and match the 2 marks on rim and tire then rebalance the tire.

 

[t.stimpson]

I ended up buying some CK375's for my truck and that fixed it. I'm not sure what it was about my old 22's that made them vibrate, could've been a dent or bad corrosion throwing them off. Road force balancing helped but never eliminated it. Hope that helps.