System: automatic transmission; cooling unit and lines.vehicle description: pickup trucks and vans equipped with 4l80-e automatic transmission.note: if your vehicle IS presented to an authorized dealer on an agreed upon service date and the remedy IS not provided free of charge within a reasonable time, contact chevrolet at 1-800-222-1020 or GMC at 1-810-456-4547. Also contact the national highway traffic safety administration's auto safety hotline at 1-800-424-9393.