Our overdrive just plain sounds weird when on so we leave it off. What't wrong.

You'll need to address these issues one at a time. The Transmission is in need of a specialist to determine whats wrong with the overdrive. By running the car without the overdrive on & functioning, its costing you miles per gallon as the engine is working harder at a higher rpm. As far as your 'not running right' issue, a proper diagnostic check by a qualified technician might serve you well.