Got a little problem having trouble trying to solve, Help ! 1981 300sd transmission,think I have all of the vacumn correct but I still have a down shift to first gear problem. But only when it warms up , Idle is at its lowest. It seems to shift down to first fine when cold. And it shifts up threw them gears fine all of the time. Can't believe there is anything wrong other than a vacumn problem but can't figure it. Help ?