Volvo VN/D13 issue

New here, sorry if improperly placed. I'm stuck and need help. 2015 VNL w/D13.
3 months ago I had a truck come in puking out of the CCV system, throwing codes for excessive blow by, and EGR temp sensor issue. Ordered a new CCV canister from Alfdex, realized bung was damaged for EGR temp sensor, R+R'd CCV/new temp sensor, repaired bung. Truck ran great for 6 weeks. It then came back because it wouldn't clear much soot out during a Prkd regen. It was close enough to our company's 250K DPF filter change schedule that we did it, it also had clear indication of an exhaust leak at the upper dpf filter gasket. The next week oil seal went in the turbo. In the past two weeks trucks had a full pm, new turbo, boots, orings, clamps, cleaned egr, new valve cover and timing cover gasket, air cleaner, dpf filter, egr/venturi/cross tube were all cleaned, someone also put a new def doser in. Truck still can only drive for 80-100 miles before showing it sooted right up, requesting a Prkd regen. If you initiate the regen it will run for 4 hours and barely burn any soot off, if I force an SCR crystal sublimation, it will clear right up to 2-5% soot count. Only code is for SCR/NOx inefficiency, truck runs like a top, drives amazing.

 

DPF inlet temp is the only one that seems to act abnormal to me. As the dosing starts and increases, it barely gets to 840 degrees before the system backs off. When it starts to purge, the inlet temp looses all its temp, then it takes it WAY to long to get back up to a decent enough temp but when it does it's about ready to stop dosing and purge again anyway, so it gets stuck in this endless loop. I'll check injectors today, forgot to mention 7th injector is new as well, got done during PM, we do them every other.
Tha is for the help so far!

 

Didn't look to be that bad, filter was sent out to be cleaned anyway and a clean one we had here was installed.

 

Both, we just kind of keep them on rotation

 

Sounds good, thank you for the direction. I'll report back.