Bad EGR cooler?

[bwake]

If you have black smoke and still have the DPF filter on it, you have a compromised DPF that will need to be replaced or removed. If you have been running it with issues, this will cause the DPF filter to take the hit and just replacing it is not the final fix. You need to find someone that will properly fix the root cause of the issues you are having with the engine or you'll find yourself in a revolving door of DPF problems.