A technician is rebuilding a drive axle. In what order should he make these adjustments?

• A. Carrier bearing preload, backlash, pinion preload
• B. Backlash, pinion preload, carrier bearing preload
• C. Pinion preload, carrier bearing preload, backlash
• D. Pinion preload, backlash, carrier bearing preload

Answer: (C)

Setting the pinion preload first establishes the correct pinion depth, which is essential for proper gear tooth contact. If the pinion isn’t preloaded to the specified amount, the mesh pattern can be wrong and you won’t be able to trust any subsequent measurements. Once the pinion depth is fixed, preload the carrier bearings to remove end play and lock the carrier firmly in the housing. A stable carrier setup is needed so that the ring gear sits in the correct position while you measure and set the mesh. Finally, with the pinion depth and carrier preload correct, adjust the backlash between the pinion and ring gear to the specified clearance. This sequence yields accurate gear mesh and reliable operation, reducing noise and wear.