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Constant Shifts Hurt Automatic Vehicles

June 30, 1995|RALPH VARTABEDIAN | TIMES STAFF WRITER

Question: My husband uses our automatic transmission as though it is a manual shift. He changes gears many times, downshifting around corners and on freeway ramps. I feel an automatic transmission should not be constantly shifted and that his driving may lead to problems. We have a Dodge Ram 250 van. Can you give us any advice?

--C.B.

Answer: Arguing over the issue might cause more trouble with your husband than his driving will cause to the transmission, but if you're asking for my technical opinion, your hunch is pretty much on the money.

The vast majority of new cars are sold with automatic transmissions, but a lot of drivers still like the sporty feel of shifting their own gears. Most automatic transmissions have settings that allow the driver to pick between first, second and drive gears.

The reason for the settings is to allow better control in hilly terrain or in special situations where you may need extra torque for short periods of time. The manufacturers design automatic transmissions to change gears for different load and speed conditions without meddling by the driver during normal driving.

But it is fun to second-guess machines and, certainly, exerting authority over a sack of gears seems good for the spirit. Unfortunately, in most cases the transmission is smarter at selecting a setting than a mere human.

The Dodge Ram has a Torque Flight Eight, a transmission with a good reputation among experts for its rugged design. If the downshifting and upshifting are done at low speeds and only occasionally, they should not damage the machinery. But it's easy to abuse a transmission by constantly using it as a manual or to get an extra measure of acceleration out of the car.

If your husband, for example, jams the transmission into first gear to help slow down the car he is asking for big trouble. The transmission should never be shifted into first gear unless the car is stopped.

Another bad practice is forcing the transmission into second gear and hitting the accelerator hard at speeds above 30 m.p.h. It will accelerate the wear on the transmission bands that run between the drum gears. Eventually the bands will fall out of adjustment or wear out.

Worse yet, shifts that are highly aggressive will tend to exert torque on the entire engine and transmission mounting system, putting extra stress on a flex plate that Chrysler uses between the engine and the torque converter to dampen shock in normal driving.

The result will be a worn-out front shaft seal and a puddle of fluid on your driveway.

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