The vac line that goes to the tranny modulator is black, and it starts at a three way that is connected to the vacuum control valve on the rear of the injection pump. The line drops back behind the rear of the engine and the firewall.

It sounds more like you may be needed a B2 piston and maybe a K-1 spring, instead of it being a vac problem. But before you tear into that make sure you vac system is all sealed and tight. Try plugging off the lines that go to the magic black bow on the top of the valve cover. That may help the situation too. Also check your tranny fluid and maybe do a fluid and filter change.

20-22" on the vac pump is in the good range for the pump. If it is jumpy you may not have had a good seal with the gauge. If there was a leak down the line somewhere it would be a constant on and the reading would be consistantly low.

__________________