4x4 to a 2x4. 2000 Rancher 350 4x4

I was just wandering . The front end needs work. The quad pulls bad to the right and is very hard to turn to the left. the differential has a mounting ear broke off and needs welded so I was going to take the front stuff off for a while to try and figure out the steering . I didn't look the machine over good before I bought it and it appears to me that the frame rusted out under the front differential and there was replacement pieces welded in . I don't know if maybe the welded pieces could have anything to do with the steering or not. What is a 424 kit ?

So an update on my quad. I ended up finding a 2002 Rancher with no motor for $200 and the frame had just a couple holes in that I welded patches in then painted the bottom with bed liner paint. The other one with the bad frame was parted out and I'm making one good one from the two.