Fourtrack steering problem


I have a 1991 Fourtrack TDX 2.8. Other than a problem with the steering being heavy towards full lock in both directions. The main issue, I think, is with the automatic freewheeling hubs. It drives fine in 2 wheel drive and fine in 4 wheel drive but when changing from 4 back to 2 I have a problem which a garage has failed to fix. Trying to make tight turns I get a juddering / grinding / knocking effect, that feels like the front wheels are trying to resist the turn. This usually disappears after driving for a while. When I jacked up the car to investigate this one wheel was free to rotate but locked when turned a short distance. The other side was already locked. Does that sound like the hubs? If so I guess replacing them with manual hubs is the answer.