Zak, Your concern on the rear axle shims is one of those things if you're not real sure about, the more you think about it the more unsure you become. Think of it in this way, the shims on the housing 'slightly' increase the housing length so the bearing cup (outer race) cannot be pushed in as far when the backing plate is installed. More shims, more play- less shims less play. Be sure to bump both axles in with a wooden block before taking your end play reading. George [Non-text portions of this message have been removed]