Hi, there might be no oil leaks because there is no oil left!! You still want to check all above.
With the wheels in the dead ahead position ( this is where some problems can occur, the wheels not being dead ahead ) because of mal adjustment of the linkage the wheels can be dead ahead but the steering box is not.
You should have a small amount of left to right free play before resistance.
To check its not too tight either remove the link end or jack up both wheels, rotate the steering from full lock to full lock, there should be no tight spot in the middle, if so too tight.