Transmission

Is an automatic transmission in jeopardy if the driver shifts into neutral each time he stops for a light or a traffic jam and then shifts back to drive in order to continue the journey?

Excess wear is being added to the transmission every time it is shifted from neutral back into gear, and there is NOTHING to be gained by shifting to neutral at lights.

Automatic transmissions should be left in gear at lights and other short stops.

Ditto to what mcparadise stated.

This practice began back in the early to mid-fifties, when the early automatic transmissions tended to “run hot”. In those days, putting the transmission into neutral at each traffic light may have actually prolonged the transmission’s life a bit by allowing some cool-down. However, this practice is no longer necessary and is to be avoided.

What is the purpose of doing that?

You actually add stress to the transmission, engine, and the remainder of the drive train when you do this.
Will it kill anything anytime soon? No.
Will it save gas? No.
Will it help anything at all? No, it won’t. So why do it?

Maybe in isolated cases that I’m sure we can all come up with worthwhile shifting out of drive at a stop light; waiting at a train crossing, pedestrian crossing, sore bunions on the braking foot etc. Otherwise, if you feel this strong urge to shift, get a manual transmission; seriously. I’m sure more ownership of manual transmissions would cut back on cell phone use and texting as well.