This type requires a small blade screwdriver to pry up the spring clip until pressure is released.
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This type shows the spring that holds around the ball mount. the C-clip is pivoted to one side to allow removing the end from the ball-mount..

The old style had a round plastic cap that was also pried up with a small blade screwdriver.
All of these require a tug to pull off the ball after the spring tension is reduced.
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2000 Winnebago Ultimate Freedom USQ40JD
, ISC 8.3 Cummins 350, Spartan MM Chassis. USA IN 1SG 11B5MX,Infantry retired;Good Sam Life member,FMCA.
" My fellow Americans, ask not what your country can do for you, ask what you can do for your country. John F. Kennedy