Jimm 2/16/2013What is meant by, ..'the Oxygen Sensor is on'? The oxygen (O2) sensor as part of the emission control and exhaust system is always 'on' - whenever the engine is running. The white smoke may be an indication of a faulty cylinder head gasket - have an inexpensive comporession test performed to check the engine sealing integrity - as a first step.
The transmission can be fixed - you didi not state whether it is an automatic or manual transmission. Check the many different on-line auto parts sources; such as - www.autopartswarehouse.com, www.partsgeek.com and www.rockauto.com for the replacement parts.