There is a new and increasingly frequent "Boing" sound while rolling along.

What is your question?

This is happening while rolling on smooth pavement. It seems to come from the rear quarter and more from the Driver side. Only once did the noise occur while my foot was resting on the brake and I did notice a vibration on the brake pedal at the time. In 3 weeks I guess this has happened about 8 times. I do not notice any acceleration, gear shifting, power, turning control, or braking issues. I cannot reproduce the noise by rocking or bouncing on the Jeep. Transmission was replaced around 86K and the Jeep has 126K miles on it. Thank you.