Barracuda won't roll

Yes, replace the seal and install the yoke. Before taking off the yoke, folks usually mark the location of the nut on the pinion before removing the nut, then when you reinstall the nut, return it to the exact location it was. That way your bearing preload should be right on. I believe torque is 240 ft lbs. Best to check the field service manual to make sure though.

Here's a thread that goes over replacing seal. There are others on here too.

http://www.forabodiesonly.com/mopar/showthread.php?t=191267