I need a new speedo cable for an 84 6.9L AT w/ cruise. Does anyone know if this model has a ratio adapter on the lower speedo cable? Thanks.

 

I would get under there and look. I am assuming a ratio adapter would be a box or something in the speedo cable. Since you have cruise, you certainly might have a little gizmo in the line right at the firewall before it goes inside the cab. It will have two small wires coming off it, and gives the speed signal to the cruise brain box. In that case your speedo cable will be shorter going to the tranny, and then a really short one going into the firewall.

The only ratio adapter type things I have ever see were on heavier trucks that had two speed rearends. The box changed the ratio on the speedo when the gears in the rearend are change to keep the speedo reading correctly.

 

Great, thanks a lot, I'll take a look under there this weekend.