I have a similar problem, my Kirby drive switch is ok but when it is engaged it flips the machine, when you push/pull the machine the drive doesn't seem to engage properly, i have noticed that there is excess movement where the handle/hoover meet. It's as if a pin or some connection has come loose or broken.
thanks for any suggestion

Gary

Vacuums - Kirby - G5 Bagged Upright Vacuum