Shaking above 65+

[On_3_Go]

Hello all, kinda coming up empty handed on this. Juat got this truck a couple weeks ago out of state and while the test drive didn't show any signs of issues, i find them later. Truck is a 2013 Av 4x4

Truck has gm 22" wheels with good tires on them. It drives straight as an arrow, even without my hands on the wheel it stays straight, smooth as glass up until 65 or so mph. The truck shakes any faster than 65, and progressively gets worse. I just had all wheels balanced today, just changed out front pads and rotors, ball joints are tight, tie rods seem good, wheel bearings are tight, u joints seem good. Yet the truck still shakes at speed. I'm really not trying to gremlin chase this damn thing so here I am. Also i havent done an alignment yet. Any help is appreciated.

 

[Fless]

Get the alignment, get the tires/wheels road force balanced, and swap wheels front to back to see if it changes anything.

 

[ChrisSRT]

check engine and transmission mounts, if worn they can allow misalignment in the driveline

 

[OR VietVet]

Where exactly are you feeling the vibrations? Front, steering wheel, in your feet, ass in the seat or in the rear?

 

[donjetman]

Take it to where they can check the tire balance and roundness (out-of-round) while on the vehicle, not off the vehicle on a separate machine.

Also check your frt differential carrier mounts: AC Delco Pt# 23104736 for the driver side, and 23104735 for passenger side. The ole rubber bushings in them get wornout.

 

[On_3_Go]

Get the alignment, get the tires/wheels road force balanced, and swap wheels front to back to see if it changes anything.

I'm gonna set up to have an alignment done in the coming days. I do have a spare set of wheels and tires with 33s on them I can swap juat to do a highway pull and rule out the wheels and tires possibly.

check engine and transmission mounts, if worn they can allow misalignment in the driveline

Engine and trans mounts look good. No signs of failure from the angles I can see from.

Where exactly are you feeling the vibrations? Front, steering wheel, in your feet, ass in the seat or in the rear?

The whole truck itself vibrates and shakes pretty decently. I may make a run on the highway and video it later today just for reference. Imagine a warped brake rotor shake when braking. That's what it's comparable to. But it's not the brakes 100%

Take it to where they can check the tire balance and roundness (out-of-round) while on the vehicle, not off the vehicle on a separate machine.

Also check your frt differential carrier mounts: AC Delco Pt# 23104736 for the driver side, and 23104735 for passenger side. The ole rubber bushings in them get wornout.View attachment 379619

I'll have to crawl under there and take a look. This is one of those things I've never thought of to check. Thanks alot. Weirdly the truck had struts replaced at 35000 miles. The truck sits now with 55000 miles. Makes me wonder if a curb was wacked hard enough to damage something. Could be wrong but I've never seen struts fail at 35k miles. Unless really abused. Truck shows no signs of abuse either, but we all know, it's easy to hide some things.

I will be doing u joints later today. As it's cheap enough to help rule out those alone.

 

[972sparky]

I did all the things you have done, road force balanced, brakes, wheel bearings, on a 2008 Avalanche and still had a vibration at around 68mph and up. Finally took it to a driveline shop and they checked the driveshaft for straight and it was bent about .040 inches. Replaced the driveshaft and new u-joints (again) and it was like new. One clue for this is if the vibration is speed only related vs RPM (engine/tranny) and will vibrate coasting down a hill in neutral.

 

[OR VietVet]

@972sparky, what I was gonna say. Whole rig shakes sounds like driveline.

 

[OR VietVet]

Said he was gonna do u joints, ck driveline thoroughly for sure.

 

[gpracer1]

Put it on jackstands, secure it and have someone go through the gears gently rasing the speed. You can then look at the driveline from underneath and look for anything out of round/vibrating/shaking, etc.