How do you clean exhaust filter on 2008 dodge 6.7?

Answer 1

It's actually a Cummins ISB, not a Dodge engine. First, you check to see if it needs cleaning.... this requires the Insite program from Cummins... trust me, it'll be much cheaper just to have the dealer hook it up than to try buying it and a version of Inline 5/6 or a NexIQ box with an OBDII connector on your own. Have them look at the aftertreatment history. If the last regeneration shows a differential pressure of more than 2.0, then it's a good idea to go ahead and do a DPF clean.
Now I'm not 100% certain of the system Dodge used on their pickups... I deal with these things on Class 8 trucks... for that year with the stuff I work on, the aftertreatment system is a four piece system - from front to back, it's inlet, Diesel Oxidation Catalyst, Diesel Particulate Filter, and outlet. You'll have to get the vehicle on stands. There should be four sensors which go into the DPF itself... follow the wires up to unplug them, and remember which ones go where... that's extremely important, or else your engine will derate from the get-go once you put it all back together.
On the trucks I work on, there'll be a clamp at the connection to the inlet pipe which will have to be removed... further up the exhaust pipe, there's typically a pipe clamp which will have to be loosened to allow some flex in the exhaust pipe in order to put it back together.
There's two ways to take out the aftertreatment system - you can either take it out piece-by-piece, or leave it together as a single unit (you'll want a small transmission jack like the one Harbor Freight sells for ~$70 - $80 for this.... it's adequate for the ones I work on, and it'll work fine for your Dodge).
On the pre-2012 models I work on, the aftertreatment system is held in place by bolts at the inlet and outlet - if they resist, DO NOT TRY FORCING THEM - they break, and you're in for a time getting them out of there. Before you try loosening those, I suggest you give them a liberal bathing in penetrating oil (IMO, the best is PB Blaster... Liquid Wrench and WD40 are kinda... crap, I think).
Each section will be held together to the next with a clamp... take those off to separate the sections from each other. Inspect the inlet and outlet for cracks and damage. Inspect the DOC for the same, plus any flaking off or cracking of the DOC face.... the DPF, ensure that it's not cracked... you can blow it out with compressed air.... I like to use a 1/2" line with an open male connector.... and you need a serious air compressor for this, as well... don't go thinking you'll clean a DPF with a the blower function of your shop vac or your little 3 gallon compressor you bought from Auto Zone.
You'll see black soot... you'll see some grey soot, as well.... if you see large clouds of grey soot, chances are, you'll need to replace the DPF, as that's typically a sign of deterioration of the inner portion of the DPF.
Once you've got it all cleaned out, you'll need to take a wire brush and clean off the remnants of the gaskets from all mating surfaces... you can use a manual brush, or a wire brush on a die or angle grinder for this.
Clean everything off, then you put it back together, being sure to replace the gaskets as you reassemble the aftertreatment system.... it helps to buy some 3M Super 77 adhesive to use on the gaskets, as well - especially when reinstalling the DPF into the vehicle. Replace all sensors you removed. Then you put it back in the vehicle... again, the transmission jack is handy for this.
As you move to reconnect the at the aftertreatment inlet to the exhaust pipe, you'll see exactly why you want the exhaust pipe to be loose. Don't actually clamp down the exhaust pipe until after you've tightened the mounting bolts.
So we go back again to where you need the Insiste software... after servicing an aftertreatment system, you want to do a forced regeneration. Before doing this forced regeneration, you'll want to replace the gasket an insulator on the dosing injector. But before you put the new insulator and gasket on, you'll want to leak test the dosing injector, and again, you'll need Insite for that.
You'll also want to replace your air filter before doing the forced regen, and you'll have to reset the aftertreatment system under the "Aftertreatment Maintenance" tab on Insite.

Keep in mind that not every aftertreatment issue or engine derate is going to be the result of the DPF needing to be cleaned... a leaking dosing injector, bad aftertreatment differential pressure sensor, bad temperature or NOX sensors on the aftertreatment system... all of them are possible problems you're having.