Neil, Thank you for your awesome article. I would like to add that one of the benefits of my kits is that they can be engaged and disengaged at any time when the transfer case is in 4-wheel drive. Some of the other kits require flipping a switch before the transfer case is shifted. This also leaves the front axle CAD with no vacuum to either the engage or disengage side of the actuator. Also, since these valves are not electrically operated they are more dependable. The main reason that the electrically operated valves that are used in other exhaust brake and 2WL kits have problems is the style of the pilot in the valve. Most industrial valves use an air pilot to shift the spool. The solenoid opens a small valve that directs line pressure (usually around 100 PSI) to shift the spool. Since our trucks are using vacuum an air pilot valve can not be used. This means that the solenoid itself has to shift the spool. The solenoid pilot valves give only a few ounces of force compared to the many pounds of force in the air pilot valves. That makes these valves very susceptible to sticking if not used on a regular basis. If you have any further questions, feel free to email me at -- email address removed --.
Bob Verhoef