X15 Cummins knocks under acceleration

2017 x15 knocks under acceleration .Loaded or empty. Gets noticeably worse when you get to 1500 rpm and around 63mph. At idle you can run it up to 1500 and doesn’t knock.
2018 579 Peterbilt. Sounds like it’s coming from the valve train but hard to judge going down the road . What could it be ? Took it to 2 different places and they couldn’t find anything. Have noticed a slight turbo surge at idle last week. And the air intake makes a “popping” noise while compressor is running

 

Did injector rail test and that passed . Did cutout test. Passed . Truck still runs good with no power loss. Sometimes it feels like the knock can also produce a “shake”

 

I can be going 65 in 13th gear at 1300rpm with boost at 30 and barely hear it . Drop back to 12th going going 65 at 1550 rpm it knocks. The second you let off throttle it goes away

 

did oil sample last week and came back good . New air filter . New fuel filter. Oil change

 

So stack is covered in white. Missing a quart of antifreeze. Also noticed that the truck has the same shake while using engine brake. This is a bummer