Chevrolet Repair: 1996 Blazer S10 4x4, blazer s10, sway bar

Question
Hello I have a Blazer 4x4 with high km on it and two days ago it started handeling like a bag of crap.I was on the hwy and it started weaving side to side it was like something had let loose.At first I thought it could be the road or a tire but checked and all 4 tires were fine,I thought maybe a ball joint or another frontend part but a garage checked the front rack and it was fine.The garage test drove it and said the could find nothing wrong with it that would make it handel that bad.The problem is at all speeds and worse with increased speed .It is the sickest feeling in a vehical that I have felt in thirty something years of driving.I drove the truck back 3 hrs fro Vancouver like that and off and on the problem was there.When I got the truck home I took the steering box out of a parts truck and put it in this one but that seems to have made little or no difference.I dont know if it could possibly be a suspension problem or swaybars.I would appreciate any help in resolving this problem.Thakyou for your time.  Warren.

Answer
Double check your tires if one of them has a broken belt.  If a tire is way out and it will cause this problem.  Also if your sway bar has broken it will cause this problem.  Another thing is check for a seized up shock if it is locked up solid it will cause that.