Hi Folks,  First time Tracky newbie.  I have a 95 Tracker 4x4, 5spd, 16 valve with a broken speedometer.  The cable is fine.  When I disconnect from the transmission and finger spin it, the speedo needle jumps.  There is an assembly that is plastic and metal that fits into the transmission, has an "O" ring, and is held in place by a 10 mm bolt.  The assembly has a gear (natural nylon color) and then a bunch of smaller parts that pass through a metal tube to finally meet the speedometer cable and an electrical solenoid with an electrical connection. 

When I spin the gear, the end into which the speedo cable insert does not spin.  Also, the local tree rats have snacked on the electrical connection.   

So...  Where can I find this entire assembly?  Does anyone even know what to call it?  Speedometer gear assembly?  Speedometer sensor unit?     

Thank you for any assistance.  Alex.