Speedo driving me nuts!

Hey guys and girls of son i am new to this i just purchased my 92 240sx hatch a few weeks ago and the anolog speedo has not been working since i got it the needle just sits past 180 and when i go 75-80 or so it raises backwards to about 150 140 or so a few other posts on the internet talked about how its not the cluster or the speed sensor its part of the wiring… can a wiring guru help me specifically on how to wire this i know the speed sensor is toward the back of the transmission i just need this more specific the car has a blacktop sr swap done to it also… HELP PLEASE! i need to get this thing safety’d:confused:

bump someone