Which speed sensor does what?

Getting a code 740 from the aw4. Trying to find out the cause. It has to do with torque converter lockup. SO anyways, there is the speed sensor in the tcase and one in the tranmission. I am guessing the tcase one goes to the speedo and the transmission one to the tcu. SO changing a speedo gear changes the speddometer reading, but does the transmission still see the wrong speed?