My tow bar slops around a bit when mounted in the 2 inch receiver on the back of our motor home --- the shank doesn't fit too tightly into the receiver --- so I set out to find something to secure it. I looked at some of the commonly-available anti-rattle devices, but quickly noticed that they are fairly light-weight --- maybe okay for a bike rack or similarly light arrangement.
An internet search helped me find a device called "Hitch-Vise." It is significantly more substantial than other devices I've seen --- the side plates are made of cast steel. Two large bolts hold the side plates together.
See here:
Hitch-Vise Fit Guide for 2 inch factory and aftermarket hitches
I'm very happy --- no more rattle, no more slop. The HT-3 cost $30 with $6 shipping. By the way - I have no affiliation with the Hitch Rider company. Just offering an honest evaluation.