O/T Blockplates and starters, not FE, 4.6

Having just had a discussion on blockplates, and some posts on their relationship to starter engagement, and knowing that some here have Crown Vics and Grand Marquis with the 4.6, I thought I'd ask.

Ever since I had my transmission replaced in my Grand marquis, my starter has had intermittant grinding on engagement. Whoever mentioned such a thing hapening after some heat soak got me to wondering. The dealer had replaced the starter twice. That cut down the frequency dramatically, but has not eliminated it.

Does anyone have any experience with intermittant starter grinding and have a sure fire cure for it?>

Seems like I should be looking into the block plate for clues, but I wiuld think if I had a block plate issue, it would grind all the time.