Found this awhile back

 

it happens to me too. it has that scratchy/grindy noise that last for about 1 or 2 second when i crank it up. weird part is it started doing that on my old f20 motor. i did a swap last year with a 48,000 mile motor. on cold start sometimes it does it, and sometimes it doesn't. is there a result as why its doing this?

 

Mine does this too. My guess is that when starter is engaged it doesn't throw the gear into the flywheel teeth as it should. My .02 as an observation on prior vehicle starters.