Thanks for the reply. I misspoke. I did not mean to say the check valves were at the wheels. I don't know if he checked the actuators or not - But I will find out.
1988 F150 Custom 4X4 300 - 6 5 spd trans
1992 F150 XLT 4X4 300 - 6 4 spd trans
1995 F250 XLT 4X4 351 5 spd trans