The matched hypoid gear pair in a drive axle: a large ring gear bolted to the differential case and a small drive pinion on the input shaft. It is known by its ratio, ring teeth divided by pinion teeth, and changing it is called regearing. Setting one up means getting pinion depth, preload and backlash right and checking the contact pattern on both drive and coast sides.
We're regearing to 4.56, so set pinion depth first, then lash, then paint the ring and pinion and read the pattern.
Never reuse the crush sleeve; it sets pinion bearing preload once, and a second crush is guesswork.
Also heard as
- R&P
- gear set
- final drive
Related terms
Hypoid gear
A spiral-bevel-like gear pair with the pinion axis offset from the gear axis, standard in vehicle drive axles.
Pinion depth
How far the hypoid or bevel pinion sits along its axis toward the gear, set with shims behind its bearing.
Set the pattern
Shop phrase for adjusting pinion depth and backlash on a bevel or hypoid set until the contact pattern is right.
Pumpkin
Shop name for the round differential housing in the middle of a drive axle, from its bulging shape.