Mechanice help please

My honda odyssey wont change gears…it was working fine and now the RPM gage moves but the speedometer is not…whats wrong with it?

Year? Auto transmission?

Transmission are the weak point of these vans. Check the fluid level of the transmission fluid. If it is not low , you need a transmission.

If the vehicle is moving and the speedometer does not work the vehicle speed sensor has failed, the transmission control module can’t command proper shifting without the vehicle speed sensor.

If the vehicle will not move and the speedometer does not move the transmission may have failed.