Your TC rides on the splined input shaft and drives the pump. The only thing that causes any forward movement is the differential internal area of the front & rear halves of the TC body, which is the area of the hole for the drive snout that rides the splined shaft. Your thrust bearing is designed to take only about 200psi of pressure, but with the small differential area your line pressure would have to be up pretty high (over 100psig) to make the converter move. I think I'd be wondering if the converter you got was the right one, and then if it may have been bad assuming you got it fully seated in the pump.

In hindsight, it's always good to measure from the bellhousing mating flange to the center of the old TC (straight edge across the bellhousing) and then to the TC mounting flange to ensure that the new TC is fully seated in the pump, and measures the same.