Smoke coming from under the cab driver side during regen.

So smoking during a regenmeans the DOC is not working efficiently. The DOC could be plugged, dirty, or simply worn out and needs replacement. A faulty injector could also be to blame due to improper spray pattern or volume. First step is to remove and clean, (or just replace) the doser injector.

 

Was the wind blowing and blowing exhaust smoke back under truck?. assuming you have a weed burner exhaust. If wind not blowing you may have a clamp on exhaust leaking or a hole. But looks like lots of moisture on the undercarriage sure it wasn’t just water vapor

 

Yep, sounds like a doser issue

 

My volvo did this at 500k

It was a blocked/clogged DEF filter

the exhaust backfilled to the turbo where the turbo and flextube met

 

Are you sure it was the DEF filter, or did you mean a DPF or DOC? The DEF filter is located on the pump and doesn't affect the exhaust flow, it only filters the fluid.

 

Yes, my bad. The DPF (big filter in the burner unit)

It can clog and make the smoke backfill to the turbo if it clogs up enough.

Thats what happened to mine.

 

Exhaust leak. Even if the DPF is severely restricted the only way exhaust is getting out of the pipe is if there's a leak. If the DPF is plugged that badly that it'll push that much exhaust out of the tiniest of leaks, you're likely going to feel a huge loss of power.