Also, check the bolts holding the starter level and in place.

My topmost bolt slowly worked its way out about 1/2 an inch and my starter would grind its teeth every once in a while. Once I set it straight again and bolted it in tight, no more problems.

So make sure its not sagging or loose.

E0 #4384 of 6535 Born Jan. 9 1998 My SVT from the ashes 147,466 miles, purchased Nov. 2002 @ 76,559 miles