A518 Overdrive transmission

Howdy guys, it has been awhile since I posted anything about my 1969 Dodge A108 Van project.
I've done quite a bit but it is a slow go on this ole girl.  
I rebuilt the 318 engine, acquired a 1992 A518 overdrive trans that I had rebuilt, new brakes and a bunch of other stuff.
What I'm doing now is rewiring using a Ron Francis wiring kit.  This is the first time I've done a complete rewire and it is intimidating.

I have a question for all you dodge guys.  I'm trying to figure out how to wire the overdrive for a manual operation. When I got the trans. everyone of my friends said it would be an easy hook up, well, no buddy seems to know how to do it. So that's my question, how can I wire up the overdrive to operate the 3-4 shift manually?

As always any help you could give will be much appreciated!

Dennis Schoessow

I hope someone chimes in on this I do not know

With the a518 trans you can lock the overdrive out, it is controlled by a solenoid on the trans and a switch on the dash or where ever you put it. Simple on-off toggle, rocker or push button will do the trick. So manual in the sense of tripping the switch, but there is no 4th gear position that you can select with a shifter.

These guys have everything you should need
https://transmissioncenter.net/shop/patc-727-to-518-46rh-conversion-kit-click-here-for-727-to-46rh-swap-wiring-diagram/

Thanks Dix, busman78 and 68bigblock for getting back to me with some good info.  The winner is however...68bigblock, your info about ( Transmission Ctr. ) was spot on.  they have everything I needed to get this trans. working the way I want it too.  They even had all the parts to convert the electrical speed-o output to mechanical.  Thanks guys!  We all know it takes a village to fix these Vintage Vans of ours and I really appreciate this site and its members.