vibration/hum at highway speeds. What to troubleshoot

[Wookiee]

My truck, 2013 crew cab, 4x4, a little over 100k miles, fully dlt'd for about 10k miles, has recently developed a hum like vibration that can be felt in the floor pan and pedal most prominently over 70mph. More like a buzz you can feel. No noticeable sound or noise associated with it. no codes, no other known issues. I am way over due for brakes for full disclosure.
I don't see anything physically wrong, but have not removed the wheel to see. it really feels like a tire issue, but no bouncing no balance/alignment issues otherwise. Tires are only about 12-15k miles old (BFG TA KO2's in 35x17's... normally very quite tires) and have been rotated at least once before. Also if i'm on a curve at those speeds, i can feel it diminish or completely disappear. when i straighten back up, it comes back.

What would you troubleshoot first?
Brakes
Hubs
Drive Shaft
Tires
What else?

I'd rule out exhaust vibration as it does not appear to be RPM dependent, but only speed. and nothing has changed on that end for the last 10k miles. Could the brakes cause this? Anyone seen this before?

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[cumminsdieselfreak]

Have you ever changed your u-joints? Also, KO2s have been known to have balancing issues.


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[RamIt]

My truck, 2013 crew cab, 4x4, a little over 100k miles, fully dlt'd for about 10k miles, has recently developed a hum like vibration that can be felt in the floor pan and pedal most prominently over 70mph. More like a buzz you can feel. No noticeable sound or noise associated with it. no codes, no other known issues. I am way over due for brakes for full disclosure.
I don't see anything physically wrong, but have not removed the wheel to see. it really feels like a tire issue, but no bouncing no balance/alignment issues otherwise. Tires are only about 12-15k miles old (BFG TA KO2's in 35x17's... normally very quite tires) and have been rotated at least once before. Also if i'm on a curve at those speeds, i can feel it diminish or completely disappear. when i straighten back up, it comes back.

What would you troubleshoot first?
Brakes
Hubs
Drive Shaft
Tires
What else?

I'd rule out exhaust vibration as it does not appear to be RPM dependent, but only speed. and nothing has changed on that end for the last 10k miles. Could the brakes cause this? Anyone seen this before?

In my own personal experience as both a car salesman & a mechanic, KO2s do not fair well on HD trucks. The tread design is highly prone to cupping and uneven wear and this is further exacerbated by the sheer weight of a 2500/3500. YMMV, but anyone I know that has put KO2s on their truck has had problems with them.

I would probably start with the tires and work your way up from there.

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[Polaraco]

My truck, 2013 crew cab, 4x4, a little over 100k miles, fully dlt'd for about 10k miles, has recently developed a hum like vibration that can be felt in the floor pan and pedal most prominently over 70mph. More like a buzz you can feel. No noticeable sound or noise associated with it. no codes, no other known issues. I am way over due for brakes for full disclosure.
I don't see anything physically wrong, but have not removed the wheel to see. it really feels like a tire issue, but no bouncing no balance/alignment issues otherwise. Tires are only about 12-15k miles old (BFG TA KO2's in 35x17's... normally very quite tires) and have been rotated at least once before. Also if i'm on a curve at those speeds, i can feel it diminish or completely disappear. when i straighten back up, it comes back.

What would you troubleshoot first?
Brakes
Hubs
Drive Shaft
Tires
What else?

I'd rule out exhaust vibration as it does not appear to be RPM dependent, but only speed. and nothing has changed on that end for the last 10k miles. Could the brakes cause this? Anyone seen this before?

Have you ever changed your u-joints? Also, KO2s have been known to have balancing issues.


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My first reaction was exactly that.

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[Wookiee]

I'll rotate the tires this weekend and see if that changes anything.

RE: U-joints, why would I need to have replaced my u-joints on a truck w/barely 100k miles? is that a normal "wear" item?

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[RamIt]

I'll rotate the tires this weekend and see if that changes anything.

RE: U-joints, why would I need to have replaced my u-joints on a truck w/barely 100k miles? is that a normal "wear" item?

It's worth looking at them for any signs of unusual wear or damage, just to rule it out.

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[Polaraco]

I'll rotate the tires this weekend and see if that changes anything.

RE: U-joints, why would I need to have replaced my u-joints on a truck w/barely 100k miles? is that a normal "wear" item?

It happens.

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[Polaraco]

I have 120K on mine and they are still holding up. I do an annual PM on the truck, including oil and filters. But my oil, after 6K, is still clear. I have to attribute some of that to the dual filters. Not a bypass.

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[03 unicorn]

I'll rotate the tires this weekend and see if that changes anything.

RE: U-joints, why would I need to have replaced my u-joints on a truck w/barely 100k miles? is that a normal "wear" item?

I had to replace an axle u-joint with 112000 ish on it. Also maybe wheel bearing. Good luck

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[Wookiee]

ok, it's not the tires. There was a little bit of cupping on the front tires (hard to tell w/the tread pattern on the KO2's). rotated them, problem still there. I've got it in a shop today to replace the u-joint and the seal at the transfer case. It has a tiny leak and had already been replaced about 50k miles ago. So, most logically, i guess that may be it. worth replacing anyway, since the seal needs replacing. If this doesn't fix it, i'll go after the wheel bearings. I'll keep y'all posted.

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