Hello
Semi Automatic are the new Paddle shift where you don't operate a clutch but tell the car when to change Up/Down a gear.
An Automatic with Manual option should only be changed when stationary
Andy C
Not all manumatic transmissions are designed the same way...it would help if you also included the year, make, and model of vehicle you're referring to.
But it's a pretty safe answer to say that nothing would happen. Most manumatic transmission are designed to allow driver gear selection as long as it is appropriate. If you were to try to do something stupid, the transmission would override your command and not allow your selection ( unlike a real standard transmission ). In the case you're describing, the transmission will very likely just remain in the gear that it was already in and allow you to either up or down shift if you wished. But if you started braking but did not downshift, the transmission computer will eventually downshift for you. The same thing with acceleration. If you started redlining the engine without upshifting, the transmission will do it anyway.
Nothing would happen that could damage your transmission. The + & - electrically changes the the internal workings of the transmission to cause the gear ratio to change. It's no different than than changing the shift lever from D to any other forward gear. But read your owner's manual. It has the best answer.
you would need to either use the paddles or gearshift lever with + and - signs on it to change gears yourself or change back into drive and let the car change gears on its own.
It would completely strip out the oscillation adjustment screw. Please don't do it.
Then you shift the gears manually. Duh! It's not rocket science.
