For the Cummins ISX engine, the flywheel housing (the rear structure that bolts to the engine block) typically requires a two-stage torque process of 74 ft-lb (100 N·m) for the first stage and a final torque of 145 ft-lb (197 N·m)
Save this guide. Print it. Put it on your toolbox. Getting the torque right on the ISX flywheel housing isn’t just about preventing leaks—it’s about keeping the transmission input shaft aligned and the rear main seal intact for the next 500,000 miles. Cummins Isx Flywheel Housing Torque Specs
Cummins switched from Unified National Fine (UNF) to purely metric on the ISX after 2005. If you try to use a 9/16" socket on an M12 bolt, you will strip the head. Use for the main housing bolts. For the Cummins ISX engine, the flywheel housing
The specific or ISX generation (e.g., ISX15, CM870, CM2350)? If you are using new bolts or reusing the old ones? Tighten bolts in a crisscross pattern from center outward
After installation, a dial indicator should be used to check flywheel housing bore runout and face runout. This ensures the transmission will align correctly with the engine.
