CarTalk.com Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Coasting in Neutral to a Stop in Automatic

I loved my stick shift truck. I would coast in neutral. I now drive an Automatic Car and I love to switch in Neutral and Complete stop and put in Drive when ready to go .Does this habit ruin an Automatic transmission or is it my imagination ?

I don’t think you’re necessarily breaking anything but also don’t know whether you’re saving anything. You are technically using the shifter a bit more than normal so things could wear out a bit quicker, I guess. An automatic does brake on its engine somewhat so you’re putting a bit more strain on your pads and rotors.

If I were you, I’d drive the car the way it was intended to be driven. Shifting a stick in and out of gear defeats the purpose of an automatic.

I don’t see a mechanical problem as a result of shifting to N and rolling to a stop. In bad winter weather I sometimes do this when I need to stop on a hill. Some shifters are easier to move past N and into R. As long as you don’t inadvertently go into reverse no damage done.

I won’t recommend this practice to most drivers because dropping the tranny into reverse while moving forward isn’t good at all. Some transmissions have an “override” to protect the transmission, but why take chances?

Coasting in neutral is most likely illegal.

No, you are not hurting your transmission by coasting to a stop in neutral. And any suggestions of additional wear are pure guesswork, not backed by any data.

Like you, I too have finally made the switch from lifelong ownership of cars with manual transmissions to a new car with an automatic. And I’ve overcome the habit of coasting to a stop in neutral. Nothing is gained from the old technique. I make the warm recommendation that you do the same.

Automatics have an overrunning clutch to allow the engine to freewheel (like running in neutral) in the higher gears to reduce fuel consumption. It pretty much eliminates engine braking in high gear. Shifting to neutral won’t hurt it but it won’t help either. Don’t bother.

I see no potential for danage to the tranny, but you’re probably multiplying the wear on your shifter linkage by many times. Lots of the parts in the shifter linkage assemblies are plastic now, so it may cause premature linkage failure if you keep the vehicle long term. Don’t know for sure.

I don’t and won’t.

Coasting in neutral is kinda dumb in an auto or a manual. In a late-model manual, the fuel injection will usually shut the fuel off if you are coasting in gear, so coasting in neutral will frequently use more gas than coasting in gear. In an auto, it is just a wasted effort and wear on the shift linkage.

If I were a passenger, it would drive me absolutely nuts watching this all the time. Its an automatic so get over it and put it in gear and leave it alone.

doubleclutch is on the right track here. If saving fuel is your goal, coast in gear. Once you have stopped, you can put it in neutral and it will save fuel because the engine won’t need to overcome the drag of the torque converter. As for the linkage problem, I don’t know about the affects of all teh shifting, a transmission expert like transman318 would know more about that.

Most automatics will freewheel while coasting when the transmission shifts itself to the lowest ratio and the manual selector is not in ;low’. In manual ‘low’ you get engine braking all the way to match speed. As the car slows further, the engine speed matches the vehicle speed and the torque converter will come into operation. Most lockup torque converters are pretty loose and as such do not load the engine excessively.

Shifting in to ‘neutral’ while coasting does not hurt the transmission other than the operation of the manual shifter i.e. movement in the shaft seal, sliding of the manual spool valve etc. Reengaging the transmission involves reapplying the ‘forward’ clutch so you would be causing extra wear on that as the torque converter is loaded by the engine against the stationary output train. I would let the transmission operate as the engineers designed it.

Where in any owner’s or driver training manual is coasting in neutral suggested ? The closest I have ever heard is on glare ice to mitigate the effects of uneven engine braking which could initiate a skid. Otherwise, I have yet to see it recomended by anyone in the automotive field.

I’ve read that the torque converter drag at idle is negligible. Heck, it won’t even hold you on a fairly steep grade. When the engine is revved above idle, the pull increases very quickly.

Guess I am kinda dumb for coasting to a stop in neutral with a manual trans, @doubleclutch please explain why. A stop ahead shift to neutral, no clutch engaged and use brakes to stop.

I’m with you. I don’t like having to push on the brakes to prevent the car from moving forward. Seems counterproductive. I’m not a fan of automatics, but my 4x4 truck is an automatic, and I do the same as the OP if there is a lot of traffic and I expect I’ll have to wait a while at the stoplight. Me, I usually coast in gear until I’m almost stopped, then I shift to N. I have one friend of mine who this habit of mine annoys, so I have to stop doing it when they are riding with me. Otherwise I catch “backseat-driver” hell. Other than that, I’ve experienced no transmission problems from doing it.

Net zero benefit for shifting. Just leave it in drive, there’s enough stuff to pay attention to without adding unneeded shifting.