One problem related to steering knuckle spindle has been reported for the 2001 Ford F-250. The most recently reported issues are listed below.
2001 Ford f250 superduty upper and lower ball joint failure w/78985 miles on vehicle. One upper was worn to allow an inch of move in wheel. Ford has a problem with premature ball joint wear as I have this vehicle with the problem, had a Mercury grand marquis ball joints failed with 40000 miles or less. F250 diagnosed at front end alignment facility they said 70000 miles is good on Ford ball joints as they replace a lot of them in 40000 and 50000 miles. Ford has determined this a wear area and will not recognize the problem. I contend this not fail until well above 100000 miles. It is not a tire, brake pads, filters, or belts.