Transmission not working properly

While driving, my transmission began to act like it was in neutral. Gas only revs the engine.
No check engine light comes on.
When trying to Shift, no gear is available although dash shows the selection.
You can hear solenoids moving when switching between 2-wheel / 4-wheel drive but car does not move, just revs the rpm’s...
The linkage is connected and moves the controller attached to the transmission under the car...
I hadn’t experienced any prior slipping of the transmission.
There is nothing leaking under the car.
Fluid levels are fine...
What can the trouble be?
I can see many other Trailblazer owners experiencing the same issue with no resolve!
Thanks!