Hi, I have a 1990 F150 with the 351 and E40D tranny and my speedo is not working. The truck revs high when going about 30, having a hard time shifting into gear which I am blaming on the speedo not working. I pulled out the speedo cable and when I twist it the needle moves, why doesn't it work when driving?

 

if the needle moves when you spin the gear on the end of the cable,than either that gear is worn, the gear in the output shaft of the trans is worn, or they are both worn enough to not make contact.

 

Sounds like the drive gear at the transmission or transfer case end of the cable is stripped.

 

I took out the speedometer cable and felt around inside the hole and there is nothing in there to feel except a cylinder right under the hole (inside), I imagine this is where the drive gear is meant to be mounted on. Can anybody confirm this?

 

Does anybody have any reasoning behind why this would be so, could he have rebuilt the transmission with a newer one?