No need to be frustrated that he doesn't care when he poops in his pants, remember, he's been doing it for 34 months, this is what he knows! It's also one of the few things in his life he can control, along with eating and sleeping, don't get into a power struggle with him over it.
The is my go-to site of reference for parents with a "poop refuser or holder":
http://www.rogerknapp.com/medical/pottytrainingrefusals.htm
My guy did somewhat of the same thing so I know what you're going through, he held his poop for up to 6 days at a time and would try to hide when he needed to go, and I was terrified he'd develop encopresis so hit the web to get help and found this site. The site is a great source of information and will take you step by step through the process of getting your son to poop in the potty/toilet. Some of the key advice is backing off and putting the responsibility on your son to use the toilet, he cleans himself and his soiled clothing, having him sit at regular intervals throughout the day and evening, not willy nilly whenever, and using "power incentives." A power incentive is one that you the parent retain ownership of, (because once a child receives a material object the incentive to do what you want them to do is no longer there) while allowing him to earn 30 - 60 minutes of use of it when he goes poop in the potty and not in his pants, whether it be a toy, video game, DVD, etc. This concept literally had my guy running to poop in the potty on his own within a little over a day!
Since you are moving I'm going to recommend you put him in pull-ups (and I truly despise pull-ups and used cloth trainers with covers over them for all my little ones, because they are diapers and don't help a child train, lol, but I respect this is your way of doing things) all the time until about a month after moving. He is possibly rebelling because he's aware of the big change coming up, he IS going to regress and possibly start peeing in his pants as well, make your move an easier transition for everyone and start using the information in the site in about 6 weeks. In the meantime you and your husband take him in the bathroom every time you go so he can see it's a normal thing, and he can learn the fundamentals of pulling his pants up and down, wiping, flushing and washing his hands, all of which are part of the potty training process.
Stay consistent with it once you begin, hopefully in a couple of months he'll be done!