So we all know the slave cylinder is a horrible piece of **** in Rangers. I had major problems with it when I had my Ranger. Well there is a company that makes a fix for the six speed issues with Tacomas. They have a ford section but they have nothing yet. Maybe it is worth a shot to email these guys to see what they can to for the Ranger. Just thought I would try and help.
SUMO Parts - OE Parts without the OE Price - FORD