Speedometer gear problem...too small, or installed wrong? (700R4)

[D-Day]

Well, I went to the dealer last week to pick up a new speedometer gear to correct my speedometer reading since I have different tires than when the trans was installed. 700R4.

It had a 41 tooth gear (I'm assuming, it says 41 T on the back of it), and I got a gear for 235 tires, 16 inch rims for 3.73 gears. I have 245's, but close enough I figure. It says on the back 35 T, which, again, I'm assuming is 35 teeth.

Got the new gear, and it was slightly smaller. To be expected, right? Less teeth, less diameter...I didn't think about it much, I just wanted it to work. Who doesn't?

Anyway, I installed the gear a couple days ago, and just took a trip to get grain and found it doesn't work. Big surprise...not. So, is there a trick to make the installation proper, or is it just too small? Now what?

I assumed you just put it in, made sure the cable was in the back of the gear and voila.

I suppose I'll have to take the damn thing out again, grab the old gear and go to the parts store and see if I can resolve it. It was a gear for a 700R4, why shouldn't it work? Blug.