Can you disconnect or bi-pass the overdrive without causing problems?

Can you disconnect or bi-pass the overdrive without causing problems?
QUESTION NEEDS TO BE MORE SPECIFIC TO BE ANSWERED PROPERLY. Rough answer: It depends. How old is the vehicle? What make and model is it? Is the overdrive electronic or not? Is it integral with the vehicles Engine Management System? (E.M.S), Does the vehicle even have an E.M.S or is it too old for that?I had a "T" reg ('79 I think!) Triumph Dolomite 2.0 Sprint with overdrive. The overdrive switch broke but the car carried on working fine.In older cars (ones without fuel injection or engine management systems) it is possible to disconnect the overdrive switch, as all it does is open up additional valves.In newer cars the likelyhood of the overdrive being integrally linked with the E.M.S (cars "brain") is high and unless you want to think about recallibrating the E.M.S to work without overdrive capability you are flogging a dead horse!You could most likely bypass such a system but you would have to know EXACTLY which terminals did what, and without a schematic or even knowing what car it is, it is impossible to tell. There is a good chance that you would cause the E.M.S to reset itself by doing this incorrectly, and that could be expensive!Cant think of a decent enough reason to want to remove overdrive capability from a car anyway. You can always leave it turned off if you want to save fuel.