GM-48007 holds the drive pinion to service the pinion retaining nut on the pinion cartridge assembly. GM-48007 is secured in a vise. The pinion cartridge assembly is placed onto GM-48007. The pinion nut can then be removed or installed and torqued using the GM-42172 Pinion Nut Wrench. Due to the high load required to break loose or fully seat the nut (approximately 500 N-m/370 lb.-ft), the pinion cannot be allowed to turn.
GM-48007 also features a square drive to secure the pinion, allowing for backlash checking. Failure to use GM-48007 will result in damage to the pinion teeth, resulting in the unnecessary replacement of the ring and pinion gear set.