section 8 of the single reduction fan drive repair manual describes how to measure backlash. The value that is of real importance is the "normal backlash" that is measured using an indicator directly on the gear teeth in a direction normal to the surface. Because obtaining this measurement in an assembled gear drive can be extremely difficult, the method in section 8 of the manual is presented which takes indicator measurements on the end of the input shaft and converts the value to the normal backlash. This conversion depends on the exact point the indicator is located (the r value discussed in the manual). What they have shown in their photos and table is the M measurement discussed in the manual. This value is then used in the equation in the manual, (8.75/Ratio)*(M/r) (only valid for a F175), to convert to normal backlash. If I assume that their r value is 1.03 inch, then I get a minimum normal backlash of 0.012 inch and a maximum of 0.024 inch by using their min and max values for M.
The real danger is being below the backlash etched on the gear set. I cannot look this up for them, but these gears should have a normal backlash etched on the gears between 0.007 - 0.009 inch. The maximum value is less critical, with two or (sometimes) three times the value etched on the gear set taken as the maximum allowable. The maximum normal backlash I calculated from their table was 0.024 inch, which is a bit high, but I would not be concerned with it, or consider it a likely cause for high noise.