When you have a moment, please update your profile to include details about your truck.
The seal can be replaced with the steering box in-place. All that needs to be done is to remove the large nut (1-5/16", I believe) that holds the pitman arm in place, remove the pitman arm with a puller, then remove the snap ring that holds the washer and seal in place.
Movement in the steering can be caused by several things. The steering box, the steering column, loose joints in the intermediate shaft, wheel bearings, slop in the inner and outer tie rods ends are some of the most common causes. When I bought my truck used (which had about 125,000 miles), I ended up rebuilding the entire front end to restore decent driveability.
Last edited by AtomicDog; 01-22-2014 at 08:18 PM.