The 1999 F-250 is part of the 10th generation of Ford's venerable F-series of pickup trucks. The shift cable on the F-250 allows the transmission to change your vehicle gears from forward to neutral to reverse and through the other gears. The shift cable does not have a specific maintenance schedule, but should be checked when you have the vehicle serviced.
Lift the vehicle off the ground using a stable and secure jack mechanism.
Remove the shift cable from the column shift lever -- this will just pop off.
Remove the shift cable from the bracket on the steering column
Push the rubber grommet through the hole in the firewall.
Remove the shift cable from the lever on the transmission.
Remove the shift cable from the bracket.
Reinstall the cable into the bracket.
Reinstall the cable to the transmission shift lever on the transmission.
Push the shift cable through the firewall and install the rubber grommet.
Reinstall the shift cable onto the bracket on the steering column.
Reinstall the shift cable to the column shift lever.
Lower the vehicle to the ground. Start the vehicle and place it in gear to test.