It does happen. We had the motor shaft shear off right after the DW raised it off the ball. It was 6 years old, and had started to make a strange noise just as we hooked up to leave for the weekend. At least it waited for us to get home before it gave up the ghost. Not a replaceable part I could buy, so a new jack was ordered.
Every day's a learning experience, though sometimes not what we expected.
2012 Jay Flight 19RD
2016 Ford F150 XLT 2X4 SC 3.5L Eco Max Tow
2010 Tundra TRD DBL Cab (Traded)
2 new fluffy Corgis, Bayley and Stanley