can't turn in 4 wheel drive

i bought a '72 chevy k20(4speed) a year ago and never got a chance to play with it. a while back i was driving down the freeway and didn't know that my little son kicked it into 4x4 and shredded the front drive line. i ended up getting it fixed. i put the new driveline in today and went to test it. the truck was working fine until i went to turn and then it started jumping in the front a little. the guy i bought it from said it had a locker in the back. the truck churps every time i turn on the street and i recently got it stuck in soft sand(without 4x4) with both the tires were kicking up dirt. the rear axel is an old eaton(i'm told) that is out of production, the front is a dana 44, and the gears are 4.56's. the t-case is an np205. if anyone can tell me what is wrong and tell me what i should do, i would greatly appreciate it. if you tell me what the name of my rear axel is, that'd be cool too. thank you.

You have a old Eaton HO72 which is one tuff axle even today (it would be a 4.57 because they only came in 4.57 and 5.14 in those trucks, front is a 4.56) It is quite normal for steering to bind and jump in turns in 4x4 with straight front axles  and for two reason, One is the the Ujoints up there are not constant velocity and the other is the wheels have a different rolling radius in a turn which can bind things up a lot at times. This is why you do not use 4x4 on surfaces with good traction as a slick surface will allow for wheel slipapage and reduced bind. If you have big tires on it it can reall get nasty sometimes and it not good on front axle. 72 is one of my favorite body style and the end of it too. They had nice simple clean lines and was a nice looking truck. 72 also has a stronger frame in front than 73 to 87 models.