transmission clean up and paint

Good morning, While im waiting for the 340 rebuild at the machine shop I thought i would send the 727 out to the tranny guy for a rebuild.
Im detailing this car pretty nice so i would like to clean up and paint the 727, my question is do i de-grease/sand/and paint it before i send it to the trany guy or after?
also any tips or recommendations are welcomed, thanks FABO...Rich