Steering wobble and pull

[1972MaineK5]

First day member and I'm posting like crazy. So yesterday out of nowhere I started to experience wobbly floating steering. Additionally when turning at low speed I experience some resistance to turning the steering wheel. And then when turning against this resistance the steering sort of "gives" and over steers in the direction I was turning. It also gives little pulls to the left as I'm driving. Nothing major but certainly startling when driving. Ok. And here is the kicker. Only happens in 2 wheel drive. If I just engage 4wd from the cab and don't lock the hubs. The truck drives completely normally. If I engage the hub's in 4wd it drives normally and if I drive in 2wd with the hubs engaged it drives normally. Anyway, I haven't really done anything other than visually check the front end. Ball joints, tie rod end's all visually look fine. Plan to put it up on jack stands today and get a better feel for the ball joints and wheel bearings. And plan to pull the front diff cover and see if anything is going on in there. I had read one post of simular symptoms that someoNE had traced back to front diff issues but no mention of when it occurred in relation to 2wd or 4wd. Though and or input would be appreciated.