Labor cost is something you can only truly get by shopping around locally. This cost will vary nationwide. Me giving you an idea of price does not consider local labor rates and related costs. I suggest contacting some local shops - here are some near you: https://repairpal.com/gmc-within-10-miles-of-north-port-florida-34291
RepairPal Certified shops can diagnose and repair your 2002 GMC Sierra 1500 HD. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.