[Fot] differential Pinion Height

[Scott Janzen]

I'm replacing the bearings in the diff (w/Timken USA) and am puzzled by the "set pinion height" instructions.  Here's what the workshop manual says (paraphrase):
 - install the pinion head bearing without the normal 0.10" spacer between it and the pinion.
- install the pinion shaft with bearings, no bearing spacer, shims or oil seal, and torque to 12-16 ft-lb
- put a dial gauge on the housing with the plunger contacting the pinion, then putting downward pressure on the gauge, obtain a maximum reading  (appears to be one of those special factory tools in the photo though none is cited)
-this reading, subtracted from the normal spacer thickness of 0.10", determines the thickness of the "selective spacer required".

Huh?  first of all, the spacer is 0.10" so how can there be a different thickness spacer?  The diagram shows no shims at this location.  Second and more important, why would the assembly move at all and produce any dial indicator readings, given that the pinion bearing assembly is torqued to 12-16 lb?  

These are not the instructions for shimming the spacer between the bearings, I understand those - though I am looking for ideas for a homemade preload gauge I could easily make up.

Are the instructions missing something or am I?

thanks!
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