Here's where I'm coming from: trucks equipped with the 727 do not have OD and do not have the TPS attachment on top of the VE pump, correct? So, if you were to install a A518 in a truck previously equipped with a 727, how would the OD kick in? How would you wire it to use a POT and not a TPS? Thanks for any info.!

 

The easiest way to deal with it is to use a pressure switch in the governor pressure test port. Gives you automatic OD operation without having to do all the wiring to install a PCM and make it happy enough to give you OD.

https://www.dieseltruckresource.com/....html?t=156988

 

Dave, thanks for digging that thread; that gives a ggod understanding of what can be done.

 

yep or just wire it to a switch that you manually engage your self.

 

would you wire it from the pressure port to a switch on the dash, and engage/disengage OD manually or am I not understanding the concept?

 

A 518 will have a wire harness with two wires coming out of the valve body that controls the OD. one (blue wire) will need a constant 12v source and the other if you wish to control it manually will need to go to a switch that operates off of ground.

 

archer 39, thanks for the explanation. One possibility would be to install a 2nd gen auto shifter with OD button and wire it as you suggested...

 

OD button on a 2nd gen shifter is just a momentary switch.

The setup with the governor pressure switch does not need a dash switch unless you want to be able to lock out OD.