Cummins ISX11.9 CM2250 – Service Manual 001-055   Gear Train Backlash, Front

NOTE: It is important that the adjacent mating gear does not turn during the measurement.

Use a feeler gauge to measure backlash between mating gears.

NOTE: A slight dragging of the feeler gauge should be felt as it is removed from the gear mesh, but force should not be required to remove the gauge.

Measure the backlash at the following locations:

• Front camshaft gear to front camshaft idler gear
• Front camshaft idler gear to air compressor gear.

Gear Train Backlash

If the backlash measured does not fall within the specifications above, loosen and adjust the front camshaft idler gear. Refer to Procedure 001-036 in Section 1.

If the backlash measured still does not fall within the specifications above, remove and inspect the mating gears for damage. If damage is found, replace the mating gear or damaged component.

Install the undamaged and/or replacement gear(s)s and measure the backlash again.

If the backlash measured still does not fall within specification after installing the undamaged mating gears, replace the mating gears.

Measure the backlash at the following locations:

• If equipped, front camshaft idler gear to hydraulic drive idler gear
• If equipped, hydraulic drive idler gear to hydraulic drive gear
• Rear camshaft gear to rear camshaft idler gear
• Crankshaft gear (rear) to rear camshaft idler gear
• If equipped, crankshaft gear (rear) to REPTO idler gear
• If equipped, REPTO idler gear to REPTO gear
• Lubricating oil pump idler gear to crankshaft gear (rear)
• Fuel pump gear to rear camshaft gear.

Gear Train Backlash

If the backlash measured does not fall within the specifications above, remove and inspect the mating gears for damage. If damage is found, replace the mating gear(s) or damaged component.

Install the undamaged and/or replacement gears and measure the backlash again.

If the backlash measured still does not fall within specification, replace the mating gears.