replacing doc/dpf gasket

Go back to where you had that done. Most shops have 1 year parts and labor warranties.

 

Cummins shops have a 12 month, 100,000 mile warranty on their parts and labor. Take it to any Cummins shop.
Frank

 

If not covered on the warranty, just go search on Youtube. I saw some videos on "how to" with drivers taking it a part and re-assembling them. I was only looking at the ones they were doing on Volvo VNL series though.

 

Yes you can do it yourself if the warranty does not cover it. It may be a pain depending on how you do it. If you do it yourself make sure that you do not bend or put a kink in the gasket. The worst ones that I have had the experience in taking apart were the 07-09 Cummins DPF's that were passenger side under the step. That is the one where you have to take the exhaust pipe off to get the step of to get the DPF out. Everything else I have every done is easy compared to that one including ones on transit buses.

 

If you end up doing it yourself, mark the DPF and DOC so they are put back together the exact same way. Any sensors or diff pressure tubes need to be removed before you break it apart. Many have holes that line up inside for the sensors to pass through and if you don't remove them, you will break them.