speedo driven gear--right or left thread.

[herc]

I am having the same problem that fordguy85, date 1-26-14 drive train thread had. One answer to his problem was a possible driven gear maybe in a right or left thread (rotation ?) of the driven gear. How do you tell the direction of the driven gear to ask for when replacing it? Info please---

[herc]

For those of you who may not know the difference in right and left thread speedometer driven gears I have answered my own question. On page 143 of NPD 10th edition of '48-'79 ford truck parts catalog there is a picture of the different driven gears. On right hand rotation the gear threads spiral upward and the left rotation spiral downward. A rule of thumb is that if the speedometer driven gear enters the transmission on the driver side (left)of the transmission it will be a RH rotation---all others are LH. FYI.

[1967Rhonda]

My issue is the speedometer cable turns counter-clockwise. It's a 67 with a 352 and T18. The speedo didn't work when I got the truck and the driven(cable) gear was worn down in the center of the threads like an apple core. I bought a new one and it was worn the same way within 20 seconds! I was able to use the camera on my phone to see the teeth on the drive(inside the trans) gear was worn almost completely down. I ordered a new one of each and installed them. With the driveshaft out, I put it in 2nd and nothing! Pulled the cable and the brand new gear was worn as bad as the previous 2! Realized that the helix of the gears was perpendicular to correct. I ordered the toploader(lean to the left) driven gear but when I installed it today, still nothing! Pulled the cluster and noted that the cable is spinning in the wrong direction! So I'll pull the tail shaft housing for the 4th or 5th time and get another pair of gears that turn the other way!!