Our plum tree has a limb that started to leaf this spring but now appears dead/dying.  There are vertical cracks in the bark.  The bulk of this limb looks dead, and smaller offshoot limbs of this limb appear to be dying (yellow/browning leaves and sap leaking).

Our tree service company looked at it and said it may be due to the late snowstorms/freezes we had and that there was damage due to thawing and refreezing.  They suggested just leaving the limb as is and wait to see if it recovers next spring before pruning the dead limb.

Any other thoughts or ideas?  This is one of the main limbs off the trunk.  I'm concerned about pre-maturely pruning such a major limb but also worried about leaving it if there's disease that could spread to the rest of the tree.