Welcome to Just Answer.
The fact that the turbo is making noise is leading me to a turbo, I know it is 2yrs old, but the actuator on the turbo controls your boost, you should NEVER see 50psi under a load, also, if you are revving the engine with it unloaded, and you boost more than 14psi, than the VNT veins are sticking.
There are a few checks that need to be done. But I am 99 percent sure your turbo is bad.
You need to pressure check the charge air cooler, block one side, pressure it up to around 25-30 psi, and see how much it leaks down. Should not leak no more than 5 psi in 1 minute. If your charge air cooler is silver, it is most likely going to leak. The silver charge air coolers were bad around leaking around the seam. I have changed LOTS. If yours is BLACK, they are less prone.
Next is the VNT actuator. This controls the boost. These leak, but usually if they are bad enough, you can hear it, and it won't build much boost. If the Veins stick closed, the boost will be uncontrollable, and the engine will DERATE and throw THESE faults.
You can check to see if the Veins are sticking by removing the pin on the actuator that connects the linkage. The linkage is on the exhaust side of the turbo, it moves up and down with the actuator. If you see black soot around the shaft, if you can move it in and out.
47- Turbo boost or air inlet pressure high
49- Turbo compressor out pressure high
51- Turbo compressor out temp high
39- VNT Veins not respond ( unknown FMI )
What is bad about high mileage EGR Detroits is when they rack up the miles, the EGR components start going out. When you replace one EGR component, you are back in the shop replacing something else. When I get one in the shop that has symptoms like yours, I check everything that will fail. This usually leads to a very high bill. Parts prices are about like this.
EGR Valve- $900
Charge air Cooler- $800