My front output shaft seal is leaking. I went to Autozone and got a new seal, but from the way the seal looks, it looks like I have to remove the front housing to get the seal out. Is this right or did Autozone sell me another wrong part? Also how can I tell what year NP203 I have. I went to the GM dealer to get a gasket for the front output shaft and there are two different designs for the gasket. The one I pulled off is totally different from the one I got. The one I pulled off sat at the bottom of the threads and had "fingers" running done the groves of the shaft. Help please.