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Removing or installing front gear case accessory drive bushings on a Cummins NT or NH diesel engine during a gear case overhaul or fuel pump drive service? Follow this step-by-step professional workshop procedure to set up the M20030 extraction pilot, draw worn bushings cleanly, align oil feed holes, configure the driver mandrel, and press new bushings flush to exact OEM depth.

Why Hammering & Improvised Drift Drivers Ruin Cummins Gear Cases

On Cummins NT and NH engines, front accessory drive bushings maintain strict alignment for shafts driving fuel pumps, air compressors, and alternators. These bushings feature internal oil lubrication holes that line up with pressurized passages in the front gear case. Technicians who attempt to remove or install these bushings using hammer blows, socket drivers, or cold chisels cause severe damage. Hammering on a soft bronze bushing deforms its thin inner liner, creating an egg-shaped profile that binds the accessory shaft during reassembly. Drift punches slip off bushing edges, gouging the cast-iron housing bore land and destroying the tight interference press-fit. Furthermore, driving new bushings in freehand frequently covers the internal oil feed hole, cutting off oil flow and destroying new accessory drive shafts within minutes of startup. Utilizing the 11-pound M20030 Bushing Remover & Installer Kit eliminates installation hazards completely. Its guided mandrel holds the bushing perfectly square, pressing it linearly to align oil holes and maintain exact factory depth.

The 5-Step Cummins NT/NH Accessory Drive Bushing Service Protocol

1. Clean Housing Bore & Inspect Oil Hole Passages: Remove the accessory drive shaft and seal assembly. Clean dirt, metal particles, and old oil residue from the front gear case housing bore using shop solvent. Locate the internal oil supply passage.
2. Set Up M20030 for Bushing Extraction (Puller Mode): Position the M20030 extraction adapter sleeve against the worn bushing face inside the front gear case. Align the central forcing screw assembly parallel to the housing centerline.
3. Draw Old Bushing Out Straight: Lubricate forcing screw threads with engine oil. Turn the central forcing nut clockwise with a hand wrench to draw the old bushing smoothly out of the front gear case housing without scoring bore lands.
4. Align Oil Holes & Prep New Bushing: Thoroughly clean and inspect the housing bore. Slide the new accessory drive bushing onto the M20030 driver mandrel, ensuring the bushing oil feed hole aligns 100% with the tool alignment mark.
5. Press New Bushing Dead-Flat to OEM Depth: Guide the driver mandrel assembly into the housing bore. Turn the forcing screw smoothly to press the new bushing into position until the driver bottoms firmly against the tool stop, setting exact factory depth and oil hole alignment.

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