There is no difference between Krsna's soul and Krsna's body. Just like we have got. We are different from this body. And Krsna is not different from the body. He does not change His body. Although He assumes several avatara, but he does not change His body.
Lecture on Srimad-Bhagavatam 1.7.51-52, Vrindavan, October 8, 1976