Need Info on Pinion Seal Replacement

As 67Dart said an impact works great to get the pinion nut off but if you don't have one I'd try to find something to hold the yoke with (large pipe wrench maybe) rather than sticking something in the carrier to hold it. Less chance of damaging anything IMO. Put some shellac sealer on the O.D. of the seal too. It's rare but I have seen them leak around the o.d. and the shellac makes them slide in easier. If you use a small plastic or hard rubber hammer and are real careful you don't even need any sort of a seal driver. Getting it started without distorting it is the only hard part. Once it's started you can work your way around it tapping it in place until it's fully seated