Have 49 GMC 3/4 ton with GM591865 4 speed transmission, enclosed drive shaft and a 5.14 rear end. When I went to hook up the speedometer cable, I discovered that the previous owner had substituted a wooden plug for the drive gear into the tranny. Have found a couple of drive gears, but none that fit correctly. The closest speedo drive gear that I have found has 13 teeth. Guessing that I need 8-9. I pulled the drive shaft off the rear of the transmission so I can actually match up the sppedo gear with the spiral gear on the tranny mainshaft. Can the drive gears be swapped out and if so, how do you remove from the housing. I have not gotten a real good look in the end where the speedo cable inserts, but it looks like a small snap ring type arrangement down inside may hold it together. No speedometer shops close either, so trying to work through local parts houses. Any suggestions or contacts that could help would be appreciated. If you have the correct gear, that would be even better.
