These 722.3's/722.4's suffer from cooked parts.

While changing B2 "dog bone" from a smaller one to a larger one did you change the B2 black piston seal, and did you note how ripples were on the shaft of B2 piston?

Now you could have cooked B1 and B2 brake bands as the skipping you are feeling(when cold) the contracting of B1 and B2 because they burned-up, and just cannot grip the clutch pack drums.

Martin