dcstrom, Have been wondering about this myself. Haven't had mine apart yet,will get done this winter along with swing arm mait.
Shows on 4-103 of the manual the drive shaft with a spring,oil seal,washer and circlips installed at the final drive end of the drive shaft .
The manual on 4-117 talks about using a fork seal driver attachment to install that oil seal etc. to the final drive end of the drive shaft, then use another size seal driver attatchment to set the drive shaft/oil seal assembley back into the final drive coupling gear to a given installed depth.
I appears that because this drive shaft assembly into the final drive has an external oil seal it shouldn't need lube unless its removed from the final drive? Let us know what you find.