In a large plastic resealable bag, combine 3/4 cup olive oil, 3/4 cup red wine, and 2 tablespoons Italian seasoning. Add bear roast, seal bag, and turn to coat. Refrigerate to marinate for 24 hours. rain and pat meat dry with paper towels.
Drain meat from marinade and pat dry. Season with garlic powder and black pepper, rubbing spices into all sides of roast.
Heat remaining olive oil in a large skillet over medium-high heat. Brown roast in the hot oil, searing all sides, about 8 minutes.
Coat slow cooker bowl with nonstick cooking spray.
Add carrots and mushroom pieces to the slow cooker, then carefully position the seared roast on top of the vegetables. In a mixing bowl, whisk together the gravy, soup, water, and soup mix. Drizzle roast with the mixture.
Cook on Low for 6 hours. Serve bear roast with the gravy mixture spooned over each serving.