Inc. Fan Clutch for 2WD Models w/ A/T Some vehicles may have a different fan/clutch/pump assembly that what was originally installed at the factory. If unsure as to the correct pump, measure across fan blade bolt-center diameter. Use pump #21010-G3928 for fans with bolt-center diameter = 5 1/4". Use pump #BA010-23028 for fans with bolt-center diamter = 4". - Inc. Fan Clutch for 2WD Models w/ M/T & OE A/C or for Heavy Duty models Some vehicles may have a different fan/clutch/pump assembly that what was originally installed at the factory. If unsure as to the correct pump, measure across fan blade bolt-center diameter. Use pump #21010-G3928 for fans with bolt-center diameter = 5 1/4". Use pump #BA010-23028 for fans with bolt-center diamter = 4". - Inc. Fan Clutch for 2WD Models w/ M/T & OE air cond, or for 2WD Heavy Duty model Some vehicles may have a different fan/clutch/pump assembly that what was originally installed at the factory. If unsure as to the correct pump, measure across fan blade bolt-center diameter. Use pump #21010-G3928 for fans with bolt-center diameter = 5 1/4". Use pump #BA010-23028 for fans with bolt-center diamter = 4". - Inc. Fan Clutch for 4WD Models Some vehicles may have a different fan/clutch/pump assembly that what was originally installed at the factory. If unsure as to the correct pump, measure across fan blade bolt-center diameter. Use pump #21010-G3928 for fans with bolt-center diameter = 5 1/4". Use pump #BA010-23028 for fans with bolt-center diamter = 4". - Inc. Fan Clutch for Models w/ OE air cond. Some vehicles may have a different fan/clutch/pump assembly that what was originally installed at the factory. If unsure as to the correct pump, measure across fan blade bolt-center diameter. Use pump #21010-G3928 for fans with bolt-center diameter = 5 1/4". Use pump #BA010-23028 for fans with bolt-center diamter = 4". - Inc. Fan Clutch Some vehicles may have a different fan/clutch/pump assembly that what was originally installed at the factory. If unsure as to the correct pump, measure across fan blade bolt-center diameter. Use pump #21010-G3928 for fans with bolt-center diameter = 5 1/4". Use pump #BA010-23028 for fans with bolt-center diamter = 4". -