2014 Silverado 1500 humming uphill at highway speed

Hayden Gordy · June 7, 2020

I have 2014 Silverado 1500. When going uphill at highway speed I have a humming and slight vibration that sounds like a bad wheel bearing. It goes and comes but keeps getting worse. I have replaced the hub assemblys, rotors, break pads, and calipers. I have been told that it is the transmission. Any thoughts?

lucas287 · June 7, 2020

10 hours ago, Hayden Gordy said:

I have 2014 Silverado 1500. When going uphill at highway speed I have a humming and slight vibration that sounds like a bad wheel bearing. It goes and comes but keeps getting worse. I have replaced the hub assemblys, rotors, break pads, and calipers. I have been told that it is the transmission. Any thoughts?

Just uphill? As in when you crest the hill it eases and then downhill disappears? Could be experiencing axle wrap. Hill = more throttle input = more load/twist on rear axle = pinion climbs = vibrations from u-joint angles being out of whack.

Makes sense in theory! Or it could be torque converter related. But if you're uphill you're in v8 mode and that means commanded TCC slip should be 0.

Hayden Gordy · June 8, 2020

On 6/6/2020 at 11:16 PM, Hayden Gordy said:

I have 2014 Silverado 1500. When going uphill at highway speed I have a humming and slight vibration that sounds like a bad wheel bearing. It goes and comes but keeps getting worse. I have replaced the hub assemblys, rotors, break pads, and calipers. I have been told that it is the transmission. Any thoughts?

Yes only when going uphill and it does it for a few seconds then stops and starts again. It goes away as soon as you hit flat ground or downhill. The U joints seem good with no play and the pinion also seems good with no play.

lucas287 · June 8, 2020

6 hours ago, Hayden Gordy said:

Yes only when going uphill and it does it for a few seconds then stops and starts again. It goes away as soon as you hit flat ground or downhill. The U joints seem good with no play and the pinion also seems good with no play.

While there might not be play in the pinion itself, its angle might not correct. You need to find the angle of your transfer case/transmission yoke first. Then, your pinion angle needs to be about 1 degree less. For example, if you're at -6 degree on the trans side, your pinion should be +5. Under load it'll torque up to at least +6 cancelling out the frequency. That's assuming you aren't getting real bad axle wrap though because it might climb more than +1 degree.