2001 GMC Sierra 3500 Engine: 6.0L V8; Reverse Rotation; Optional Duty Thermal Fan Clutch;. 2001 GMC Sierra 3500 Engine: 8.1L V8; Reverse Rotation; Severe Duty Thermal Fan Clutch; Old Body Style;. 2002 GMC Sierra 3500 Engine: 6.0L V8; Reverse Rotation; Severe Duty Thermal Fan Clutch;.
