Cummins ISX 3689641 Idler Gear PAI 172026OEMCROSS REFERENCE: 3685158 3686778 3690448 3689641 APPLICATION: Cummins ISX Multiple Use Application. DETAILS: Genuine Part BRAND: PAI 172026OEM Cummins ISX 3689641 Idler Gear PAI 172026OEM. Truck repair parts and heavy truck parts. Maintains gear synchronization and supports consistent engine timing control. All components are proudly manufactured in the U. S. A. by PAI Industries Inc., an ISO9001 certified company with over 50 years of experience in