The pinion gear is installed along with the yoke. This is the time to set the pinion preload. The nut is torqued until the pinion has 17-27 in. lbs. of preload. This means it should take 17-27 in. lbs. of torque to turn the pinion with new bearings. An important issue here is shims and shim thickness between the bearing and pinion. When you're using a good, used gear set, stick with the shim(s) already with the gear set. If new, you will have to determine shim thickness by temporarily installing the ring and pinion and lapping gears until proper shim thickness is determined. This is a very tedious process.