I need an inch-pound torque wrench to set up the pinion bearing preload, a dial indicator for backlash, a shim pack and indicator dye for setting the tooth contact pattern, and all new bearings for the pinion and the carrier. An arbor press, a bearing splitter, and a couple of gear pullers are almost a necessity. I've done some quick and dirty gear changes in the pits of a race track, once lying under the car on 120-degree asphalt, but I was not the least bit concerned with reliability, gear noise, or even getting further than taking the checkered flag in a few minutes. (We won the race, BTW!)

Doing a sloppy setup on a street-driven gearset is just wrong in so many ways! I'd be ashamed to take advantage of anybody like that!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!