Tachometer drive cable - Farmall 806

I pulled off the housing tach connection, inside it was the gear assembly and the teeth seemed fine. What looks like the problem is that the gear assy has a round shaft and my cable is square. Could it be that there should be a bushing or something that sits inside for the cable to connect properly? If not I am told at the local dealership that the small gear assembly is over $55 and it appears that I should be able to put a bushing in it.

Am I missing a part or something, I have a hard time seeing how the cable was able to ream out a perfect round cyl in this shaft without tearing up the cable? Thanks

I put a cable on a 706 about a year ago, and it seems to me it had the larger, round end on the connection at the engine. Are you sure you have the correct cable?

For other applications, I have obtained an adapter sleeve from the parts dept. at a heavy truck dealership that will fit inside the larger, round drive, and accepts the smaller square end of the tach cable. If you find a good partsman at a truck place they may be able to help you out, if the cable you already have is correct, or you don't want to change it.