1991 F150 Starter

Hey all - I have a 91 F150 5.0 V8 4wd farm truck. It's in good shape and has been running well. However lately it started having trouble with...starting. Occasionally on turning the key, it starts griinding REALLY loud, and doesn't even crank/turn over. I assume this means the starter is shot. However, I have attempted to find where the starter is located so I can fix it when it finally does die, and I haven't been able to locate it. Can anyone tell me if:
1) I have identified the problem correctly?
2) Where to find the starter?

thanks
Joe

The grinding upon attempt to start is probably the pinion gear on the starter not meshing with the ring gear on the flywheel. You may have to replace the ring gear. One would think that the teeth on the flywheel would be in a different positon and sometimes it would mesh all right, but the flywheel usually stops in the same place because it is on the cylinder with the most compression. The starter is at the back of the engine on the passenger side of the truck. Just follow the heavy positive cable back from the battery.

If it just started this it is probably just the starter drive that needs to be replaced. It has a sprag that wears out and causes the problem you describe. If it has been grinding for some time then ring gear replacement is more likely. If there is an electrical rebuilder in your area the drive can be replaced relatively inexpensively