A second opinion on stop-and-go

Dear Tom and Ray: I was reading a book about cars in which the author stated: "Stop-and-go rush-hour traffic is a prime candidate for spawning high automatic-transmission temperatures. Placing the transmission in Neutral during long stops will help dissipate some of that internal heat, because the clutches and other components aren't generating the necessary friction to keep the car at the ready. This helps considerably in cooling the unit." Please offer your second opinion regarding this driving practice. If you agree, comment on what you would consider a "long stop." I interpret it to mean stops of the duration that normally occur at intersections when the light is red.

Michael

Tom: I make a "long stop" every morning ... first thing when I get up. Is that what you're talking about?

Ray: I don't think so. Michael, the author is correct that putting an automatic transmission in Neutral will help keep the transmission a little cooler. But the question is, at what cost?

Tom: Every time you move the transmission between Neutral and Drive, you torque, or "twist," the entire drivetrain. That means one thing slams into the next, which slams into the next, and on down the line. Every time these drivetrain components get slammed together, they get a little closer to wearing out or breaking. In our opinion, that kind of wear and tear is more harmful than normal stop-and-go transmission temperatures -- for which the transmission was designed.

Ray: Now, if you really are stopped for a long time -- and I don't consider a traffic light a "long stop" -- then you should put the car in Park, turn off the ignition and read a book. I would consider a "long stop" a minimum of three or four minutes. You'd be hard-pressed to find a traffic light that lasts that long (although some of them sure feel like it).

Tom: I know there's less and less for us tinkerers to do in our cars these days. We're reduced to just putting it in Drive and stepping on the gas. It's boring!

Ray: But resist the urge to monkey with the automatic transmission, Michael. If you're really antsy, try dusting the dashboard.