[Mathew21]

This reply was copy and pasted from another site.

With a 2wd steering box the pitman arm moves side to side and the 4wd moves front to back. The sector shaft is different which won't allow you to just swap pitman arms. The 4wd box has a through bolt holding the pitman arm onto the sector shaft whereas a 2wd bos uses a nut and washer to hold it on. You need a 2wd steering box if you're doing crossover steering otherwise the 2wd box won't work unless you install a 4wd sector shaft. I believe the year difference for the fitting change was 1980 and earlier for the flare fitting hose and 1981 and later for the metric O-ring style hose.