1975-1976 Chevrolet Trucks Transfer Case Diagnosis Brochure. Full Time Four Wheel Drive Transfer Case Diagnosis. Introduction: Chevrolet dealers are enjoying increasing sales of all kinds of recreational vehicles - with a dramatic increase in interest in Chevrolet's equipped with four wheel drive. Why this program is timely: With an ever-increasing number of Blazers, Suburbans and Pickups equipped with full time four wheel drive in service, we believe that it is important that every Chevrolet technician become familiar with the unique characteristics of this system, in order to ensure customer satisfaction with these rugged recreational vehicles. Condition: Good.