Shaft adjustment on rear axle of m38a1

[serge]

Hello
During the dismountage of the shaft of the rear axle of my JEEP M38A1C (in the aim of replacement of the inner oil seal), I saw some shims between the bearing and the bearing retainer.These late where only on the left side of the axle.
On the technical manual I own : TM 8014 OPERATION AND ORGANISATION MAINTENANCE , there is no explaination about these parts. I suppose that they should be used for a specific adjustment
Is any body who could to explain me the method that I have to follow for the adjustment using these shims.
Regards