Is Adam in season 4?

Negative

No and I am glad. The big whiny butt, "I work too much and never see my faaammulleee"
What does he think we made of life? No rest for the weary or wicked unfortunately.

Adam has started his own wrecker company called Gazolla's Towing and Recovery. Highway Thru Hell really didn't cover too much about him quitting JDT like interviews later on. I knew he wanted to be closer to home and thus his family while Jaime Davis wanted to keep him in Alberta much of the time. I know he was his #1 man and all but now Jaime Davis not only didn't have him back as an employee, but he's now a competitor also working the Coq.