I am the original owner of this 2008 F350 Diesel with 37K miles. In October the dealer said the computer had to be flashed due to an update for the Regen cycle. Before the update, the "cleaning exhaust filter" warning would display, and you would hear a slightly louder diesel knock when occurring.
Now after the reflash, it doesn't display when it goes into regen, and heavy white/blue smoke is coming out of the exhaust for about a half mile or so. The engine has a loud diesel knock when this occurs.
I know that with the new flash a lot of people have said that the message comes on for about 2-3 seconds then goes away and does not come back on. You can miss the message real easy with it only being on for 2-3 seconds.
I do not know about the smoke. I have not heard or read anyhting with the smoke after the flash though. Hope this helps.
My truck smokes like that as well in the winter time. It doesn't do it as bad when the weather is warmer. It doesn't smoke during the whole regen though, probably for like the first minute or so and then goes away.
My '10 will billow out a smoke screen on cooler days. It normally lasts a couple of minutes about a couple minutes after a regen starts. On a recent 30mile downhill run on I-80 from Tahoe to Auburn, CA, it was belching out smoke for over 20miles until I could get off the freeway and put it in park to turn it off. Annoying, to put it lightly...
My job 1 2008 does this only when I get a build of fuel when I regen and not burning it off. I do mostly city driving. So if truck goes into regen and then I have to sit at a long light it will smoke when I pull away from light.
There is an issue from a TBS about the CAC but it does it when the air is moist and cool.
I've seen this about 3 times this winter including yesterday on the way home from work. My truck went into regen sitting in traffic on the highway. When I applied throttle to get going again, it blew out white smoke on the guy behind me. It was soo thick he had to move to the next lane. It's quite embarassing....
I don't know if his helps, but I took my rig in over xmas break for smoke issues exactly like yours. They said they test drove the truck and couldn't duplicate the smoke even though they wrote the same odometer in the mileage_in and mileage_out boxes on the customer writeup/receipt, and I know they didn't because I was there sitting in the lobby watching and waiting for them to finish. Wouldn't have made any diff since it wasn't about to go into regen anytime soon.
The conclusion was everything was normal and they referenced the TSB about water buildup in the CAC and smoke due to moisture on humid/rainy/cold days (which doesn't apply to the '10).
There was reference to Ford Engineering investigating this issue and to check OASIS periodically for updates... That blurb was dated back in Aug '10.
I asked the Service Adviser 'when' I should check back. He didn't know.
A friend with the same truck billows out smoke during regen also. He took a video during regen and showed it to his dealer. I watched it and told him it's the same exact thing I get. His dealer said it was perfectly normal also.
I sent a note to Corporate, and got no response.
Don't know about your knocking noise, but mine certainly chatters/sounds raspy a lot more during regen. Can't not notice it unless my radio is cranked.
Mine did it for some time as well as a guy I work with. Both trucks are Job 1's. Both were eventually diagnosed with a bad sensor on the DPF/DOC pipe assembly. It took the dealer 3 times to finally find mine. It was actually in the middle of a regen when I pulled into the dealer for last time. I drove it inside the service bay area, left it in drive, set the parking brake and let it regen it's little heart out and fill that place with smoke....
My truck was also eventually diagnosed with a leaky turbo so that might have been it too...