Hi,
possibly too much vacuum can cause flaring, this can be regulated by the vacuum modulator ( I had flaring between 2-3 shift last year, fixed it by reducing vacuum with modulator), now I drive without vacuum (just to test it) connected so there shouldnt be any vacuum reducing pressure I guess. But then again there is no 2nd gear for me, not even manualy, so I guess its some sort of command problem. I am working on acquiring another valvebody and it seems I may have found somebody to sell me the VB for not so much "knock knock", but its gonna take a month (until the seller comes home) and then I will install it and share the results. I may even fix the old valvebody and then sell it to someone in my kind of situation if I find the stuck valve.