ÂHow does the funny "H" pattern that I am moving this shift knob through have any relation to the gears inside the transmission? What is moving inside the transmission when I move the shifter?
When I mess up and hear that horrible grinding sound, what is actually grinding? What would happen if I were to accidentally shift into reverse while I am speeding down the freeway? Would the entire transmission explode?
The transmissions used today may have four, five or six speeds forward, but all have one speed in reverse. The reverse gear is necessary because the engine rotates only in one direction and cannot be reversed. The reversing procedure must be accomplished inside the transmission.
A band is a steel strap with friction material bonded to the inside surface. One end of the band is anchored against the transmission case while the other end is connected to a servo. At the appropriate time hydraulic oil is sent to the servo under pressure to tighten the band around the drum to stop the drum from turning.
Most of the transmission problems starts from overheating. Under heavy load, such as when towing a heavy trailer, rocking the vehicle from the snow, having continuous stop and go traffic in hot weather, racing, etc. the transmission overheats. At higher temperatures the transmission oxidizes, losing its lubricating qualities and leaving deposits all over inside the transmission. If you'd check the automatic transmission fluid in an overheated transmission, it would be dark and dirty, with a strong burnt smell. Exposed to the heat the rubber seals, O-rings become hard and brittle. The metal parts warp causing valves to stick in. All this, sooner or later, results in transmission failure. For example, a friend of mine has burned his automatic transmission when he was spinning the wheels too hard trying to free his shiny Audi from the snow; it was on the next day after he bought it!