Hi James Hughey,
I had the same problem in my truck, all I did to fix that problem was replacing the power antenna mast (the metal extended portion). All the grinding noise that you hear from the motor is the nylon cable that is broken, this nylon cable extends and retracts the antenna. the broken part of this cable is touching the teeth on the gears inside the motor that's what makes the grinding noise.
You can get the power antenna mast from the dealer it costed me 35.00 dlls. this will do the job.
Here the link where tells you the step by step on how to replace the antenna mast.
Tuesday, July 8th, 2008 AT 1:53 AM