If you're having trouble doing the required contortionist moves required to see the speedometer cable connection at the speedometer...do this. Find a board, I like one about 12" or so wide and about 4' long. Place one end of the board on the truck floor under the steering wheel, place the other end on a chair, saw horse or something else so it's level. Now you can comfortably lay on this temporary work platform and look and work under the dash.
Oh, now that you can easily see the back of the speedometer, do as suggested and just unhook the cable until you can buy a new one at Napa or from one of the many online vendors.
Good Luck,
RonR
Last edited by moparguy; 01/13/2018 12:22 PM.