How does a 1984 Corvette 4 plus 3 overdrive work?

Answer 1

1984 Doug Nash overdrive should work the same as the other c4 corvette's that had these bolted to the back of the super t-10 transmission to avoid the gas guzzler tax. They usually work by not engaging in first gear, then, engaging in second, third and fourth with the ability, as long as the engine is not above a prescribed rpm so as to explode the engine, to jump back into the standard gear upon depressing the gas pedal sort of like going into passing gear. I like the Doug Nash. It works well if you change the fluid and filter ever ten thousand miles as recommended. I do not know for sure, but I think that since the Doug Nash was an after thought, the unit is bordered to closely by the exhaust system where it forms a Y into the catalytic converter and so will overheat and destroy the fluid. Mine works just fine, and I hear that the switch to a Richmond six speed costs about twice as much as to rebuild the Doug Hash and lasts about as long. I use the overdrive on the highway mostly and the standard four speed in town.