So just did a 1,500 mile road trip this last week through southwest Colorado mostly in Durango, Silverton, Ouray, Ridgeway and Telluride. Had a lot of fun and the truck ran well but the valley turbo started making wierd noises going up and down the steep grades when using tow haul and/or the turbo break. Only happens when coasting and as soon as I apply throttle and the veins change position it goes away. Remember, this turbo was new and has already been rebuilt once by Danville after it failed at 700 miles.
Here’s a video for reference:
https://youtu.be/QG2C7EWT__k
I would be looking for an exhaust leak up to the valley charger. The drive pressure is going to the moon while the vanes are closed to operate as a brake.
It could also be the turbo but an exhaust leak would be easier to spot first.