There are three of these slots that lock the pieces that rotate with the housing at all times.

Adjustment measurements are made between the plates at A on all three slots while Disengaged. These are added together and divided by three for the average. Then measured again Engaged in Low Range and the engaged average is subtracted from the disengaged average and it should be between .042" and .046" Any amount removed from shims at 1 needs to be added to shims at 2.
This process is repeated for the gap between plates at B Disengaged and Engaged in High Range. Any amount removed from shims at 3 needs to be added to shims at 2. The total shims 1 + 2 + 3 must equal .205"

It was determined that .005" needed to be removed from each 1 and 3. Starting out 1 had .075 consisting of 3x .015 and 3x .010 and 3 had .070 consisting of 2x .015 and 4x .010. Shuffling these a bit 1 now has .070 consisting of 2x .015 and 4x .010 and 3 has .065 consisting of 3x .015 and 2x .010. Leaving these three left over, one from each slot.

Removing .005 from each 1 and 3 means .010 needs to be added at the Center 2. the shape of the shims at 1 and 3 are the same but the center shims are different and cannot be interchanged with 1 or 3. So I made these three from .010 stainless steel shim stock. Shown here with the .015 I used as a pattern. I remeasured A and B when engaged and they are in spec now.

With the gasket surface cleaned it is installed again with inner snap ring, thrust washer, inner and outer hub, spacer ring and outer snap ring.

Looking down into the layers of plates, low range in front, high range in back and the separation plates in the center, and one of the three sets of shims.

And the front half of the tractor with its gasket surface clean and ready.