Bad vibration 2019 pete 389

I bought a 2019 pete 389 with x15 565 hp cummins, 2050 torque, 18spd, 46 rears,410 ratio. Since driving it off the lot it has had a funny vibration when in the throttle in 7th direct between 52 and 58 mph. Nothing when coasting or deceleration. It has gradually gotten worse over the months. Truck has 33k on it and now. Starting last week when in 7th direct climbing a hill loaded at 80k it will randomly pop out of gear and make the whole cab shake with a loud bang. After that it wont go back in gear, you have to downshift then when needed you can put back in 7th. Theres no rhyme or reason to when this happens. I have had it at the dealer and they measured drivline angles etc. Found nothing wrong. Now they want it back to tear down the trans. Unfortunately coming into winter i cant afford to lose 2 or more weeks of work for this. The dealership has agreed to let me run it until winter as long as it stays in warranty. Also passenger window doesnt work anymore, right side dash display doesnt work and roof leaks when it rains. So anyone have these issues or suggestions? My main concern is the trans/vibration.

 

I am aware of the gear not fully seating, i do in occasion have to bump the throttle to engage 100%. That issue is definitely eliminated. I'm sure the dealer will figure it out eventually meanwhile I will just have to run it and Skip 7th whenever possible until the work ends.

 

I asked about a loaner truck or a rental they said that they do not offer anything like that.

 

Thats certainly good information but my vibration goes away when you let off the throttle. I think if it was the driveline it would vibrate at all times!?