So will a pot meter work on a 47rh to engage and disengage the overdrive. If not what will besides a switch.

 

Yup it will work just like it did with your 518. You will need to either use a toggle switch to engage lock up, or use a pressure switch to get it to lock up.. Or 3 position toggle on/manual off/center/ auto using a pressure switch

 

What kind of pressure switch exactly or where is it mounted at elrabrate a little im a

 

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