Thayer:

I called Roy (great guy by the way) and he told me that it is a high probability that the B2 piston is failing and needs replaced, he said they sell many of these and it is a common part to fail. Right now it comes out of gear between 3 and 4 but in time he said I would loose all forward gear capability.

I'm going to get the B2 piston (and extra seals) and give it a shot.