CUMMINS:
• Cummins 4B3.9/4BT/B4.5 4BT 3.9L (1983-1998)
• Cummins 6B5.9/6BT 6BT 5.9L (1989-1998)
• Cummins ISB6.7 ISB 6.7L (1998-2026)
WHITE:
• White 60/80/100/120 Cummins gasoline engine conversions (1975-1995)
• White 125/140/145/6124 Cummins gasoline engine conversions (1975-1995)
• White 6125/6144/6145/8310 Cummins gasoline engine conversions (1975-1995)
• White 8410 Cummins gasoline engine conversions (1975-1995)
IMPORTANT:
159-tooth flywheel ring gear for Cummins B-Series and ISB engines. Fits 4BT (3.9L), 6BT (5.9L), ISB 6.7, and B4.5 variants. Do NOT confuse with 127T (3905427), 138T (3902127/3908546), or 173T (3903309) — Cummins uses four different tooth counts. Count teeth on your existing ring gear before ordering.
Used in White tractor conversions, industrial/agricultural equipment, and medium-duty trucks. Also fits ISB 6.7L (1998-2026). Starter grinding or no-engagement typically indicates ring gear tooth damage — inspect teeth in the starter engagement zone. Follow engine service manual for installation procedure.
⚠️ 159T variant. Four Cummins counts: 127/138/159/173. Count existing teeth.
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