2020 T680 Makes Annoying Hum That Pulses When Engine Is Engaged

Hey all. I just bought a brand new 2020 Kenworth T680 with a 450 X15 efficiency engine and the 12 speed eaton fuller automated transmission, 2.64 ratio. Only has 2,000 miles on it right now and started making this noise on its first load.

When the engine is engaged in pulling at all, no matter what gear it’s in, I hear this “humming” sound that pulses, or rather goes loud-soft-loud-soft. Overall the sound is very low and not terribly loud but because the frequency is so low it is very annoying to my ears to listen to all day everyday...

I can’t for the life of me figure out what it is. It seems to be coming from the driver side of the truck and I can feel a mild pulsing vibration on that side through the floor in my feet and also if I touch the steering column housing. If I turn up the radio loud enough it can drown it out, but I don’t always want to listen to something. My 2015 Pete 579 I just traded in never made this noise. It goes away when the engine coasts in neutral or when the jake brake engages. I don’t think I can stand to listen to this hum/pulse for the next 3-4 years until I trade it in...it’s already driving me nuts and I’ve only delivered two loads with the truck thusfar...

 

Constant noise. Anytime the engine is engaged it makes the noise. I can hear the compressor when it engages. Makes kind of a rattling sound but then it goes off once the pressure is built up. This noise is separate and constant.

 

Warranty only covers things that when they stop functioning. As long as the truck runs, the warranty and dealership aren’t going to do crud about it. The warranty doesn’t care whether or not the truck makes an annoying noise...