So I recently changed gears in my rear axle from 2.73 to 3.42 and calculated that if I change my transmission gear from my 37 tooth gear to 45 tooth it would show me fairly accurate speed on the speedometer. I found a gear on ebay and ordered it. It said it was for 700r4, 4l60 and th400 but now as I removed the one I have the new one wont fit my gear housing. Any ideas? I measured the gearshaft to be .5mm thicker than the one I have installed. The shaft is also 7mm longer and the gear itself is 4.2mm bigger in diameter. Will the gear fit at all or do I need to get a whole new combination of both drive and driven gears?

 

You will need the correct housing, a 45 tooth gear needs an offset housing.

 

Got it, got the part number also, thanks!