Hi, I don't have a hitch rattling problem, but what you have pictured, in my opinion, would only work if you drive around with the hitch in the receiver without your trailer attached. I don't think it would be strong enough to hold things in place with a real load on it. [trailer and WD hitch installed] I had thought of makeing and useing a thin metal wedge that you can tap in place either on the top or bottom of the receiver.
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2005 Safari 25-B
"Le Petit Chateau Argent "
[ Small Silver Castle ]
Blue Stripes, American flag, Edition
2000 Navigator / Equal-i-zer / P-3
AIR #12144