ACDelco Auto-Trak II Transfer Case Fluid – 19540587 (Replaces 10-4017, 88900402, 12378396, 12378508) Keep your GM four-wheel-drive system performing at its best with Genuine ACDelco Auto-Trak II Transfer Case Fluid. Designed specifically for electronically controlled transfer cases, this premium blue-tinted fluid delivers smooth engagement, superior lubrication, and long-lasting protection under demanding driving conditions. Engineered to meet the exact specifications of GM vehicles, it helps reduce wear, prevent shudder, and maintain proper operation in Auto-Trak and Active Transfer Case systems. Ideal for SUVs and trucks that require precise fluid performance for torque management and seamless AWD/4WD transitions. Features & Benefits --- Exact OEM Replacement – GM Part No.