05 4x4 making noises when shut off

Service 4wd light has started coming on intermittently lately - and then the other day i was sitting in a parking lot, reading reddit with the engine off (key in ignition, but off) - and it sounded like someone was kicking the truck. Every 30s or so, there'd be a weird clunking noise. Got out to look around - nobody there. Then i heard it come from under the truck. Climbed under to have a look - so of course, it stopped. Waited for a while, then there was a bit of a wheeze and clunk - i think from the front drive shaft area.

I'm thinking some kind of solenoid issue? Before i bring it to the shop, is there anything i can do to fix/solve on my own? (I'm a computer guy not a car guy - so ELI5, please)