Benificial for an auto tranny??

[lawnman]

Guys I was wondering, is there any advantage or disadvantage to bumping an auto tranny into neutral while at a stop light or stopped in heavy traffic? I ask because I find myself doing it often at stoplights and not having to use as much brake force to keep the vehicle at a stand still. Thx!

 

[SteveSRT8]

Just depends on the vehicle. Older cars appreciate the load reduction especially if pulling AC etc. in hot traffic.

newer cars are so carefully controlled they won't even notice...

 

[01rangerxl]

The main disadvantage, IMO, is the risk of a stretched, broken, or otherwise worn out shift cable just because it's getting so much more use that way. A broken cable can strand you, and many are not easy to replace because one end is at the transmission and one end is buried in the column or center console. Tendency to break varies by model/design, but there are multiple cables we keep in stock at work. GMT360 cables (Trailblazer) are the hottest sellers by far.

If it feels like the vehicle is pulling too much at a stop, check to make sure idle is normal.

 

[lawnman]

Ok thanks makes sense. 1998 Nissan frontier 2.4L with 90,000 miles and my 2014 tundra 5.7L.

 

[demarpaint]

This has been discussed here before, the bottom line is there is zero advantage to putting an automatic transmission in neutral. In fact it might even be detrimental to the transmission. Unless you're stopped dead in traffic due to an accident and can't move, or at a RR crossing where it takes several minutes for the train to pass there is no benefit in putting the car in neutral.

I gathered from the discussions that there was more wear on the transmission and linkage engaging and disengaging it than just leaving it in drive and let the transmission work the way it was designed to.

It will be interesting to see where this discussion heads.

 

[badtlc]

Ford says to put it in park when stopped to let it cool if you have been doing heavy towing or the transmission is hot for whatever reason.

 

[Kawiguy454]

IMO Absolutely it is beneficial. The friction you feel in gear while stopped is the fluid in the TQ converter dragging on the engine. In response the ECU inputs more gas to keep RPM's up. Extra fuel is extra energy ...that energy is converted to heat in the fluid and wasted needlessly. The extra heat also contributes to fluid breakdown and so on especially in hot stop and go traffic. To this day it is a habit I have at every stop light and the extra fuel is used to power my air contitioning.

 

[dishdude]

There will be a time you'll forget it's in neutral, hit the gas and while it's still reving up at 2500 RPM dump it in drive.

 

[NHGUY]

I'm surprised by now they haven't come up with a computer scenario for that...sit at a light for more than 30 seconds,and the computer will automatically shift the trans to neutral,step off the brake and it re engages the transmission to the gear range chosen on the shifter.

 

[Skittles]

Originally Posted By: dishdude
There will be a time you'll forget it's in neutral, hit the gas and while it's still reving up at 2500 RPM dump it in drive.



yep

 

[badtlc]

Originally Posted By: NHGUY
I'm surprised by now they haven't come up with a computer scenario for that...sit at a light for more than 30 seconds,and the computer will automatically shift the trans to neutral,step off the brake and it re engages the transmission to the gear range chosen on the shifter.


it already goes beyond that. many modern cars turn the engine off at stoplights.

 

[SatinSilver]

Or be on an incline and go flying backwards into the Ram truck behind you.

 

[Donald]

If you think you might fall asleep white waiting, put it in Park.

 

[demarpaint]

Originally Posted By: satinsilver
Or be on an incline and go flying backwards into the Ram truck behind you.


Or take your foot off the brake get rear ended and launched into..............

 

[zach1900]

In drive at a stop isn't the transmission technically slipping the whole time?

 

[zach1900]

Originally Posted By: Kawiguy454
IMO Absolutely it is beneficial. The friction you feel in gear while stopped is the fluid in the TQ converter dragging on the engine. In response the ECU inputs more gas to keep RPM's up. Extra fuel is extra energy ...that energy is converted to heat in the fluid and wasted needlessly. The extra heat also contributes to fluid breakdown and so on especially in hot stop and go traffic. To this day it is a habit I have at every stop light and the extra fuel is used to power my air contitioning.

Why do most cars run at a higher rpm in neutral?

 

[eljefino]

I figure the slip into neutral isn't so bad, but the bump back into drive will get you with wear.

 

[440Magnum]

Originally Posted By: NHGUY
I'm surprised by now they haven't come up with a computer scenario for that...sit at a light for more than 30 seconds,and the computer will automatically shift the trans to neutral,step off the brake and it re engages the transmission to the gear range chosen on the shifter.


If it actually saved any fuel to do that, they would have done it. Heck, there are now a number of car models that SHUT OFF under those conditions and restart when you touch the gas! Bottom line, as others have said, modern torque convertors practically disengage at idle anyway, and so almost no additional fuel is burned (and almost no heat generated) from leaving the trans in gear. On an older car with a carb, big cam, fast lopey idle... yeah, it saves a lot of heat generation to drop it into neutral if stopped for more than half a minute. But not on anything remotely modern.

 

[440Magnum]

Originally Posted By: zach1900
In drive at a stop isn't the transmission technically slipping the whole time?


No. The fluid in the torque convertor is churning and shearing, so in older vehicles where there's no computer to slow the idle down when the trans is in gear, a lot of excess heat is generated. But nothing is "slipping" as in friction materials rubbing against each other. Modern cars deal with it much better- the computer knows when the trans is in gear and maintains the idle speed. Older cars were set up to idle faster than necessary so that they wouldn't stall when in gear, the AC on, and a heavy load on the alternator. When any of those loads isn't there, the excess idle speed just heats the convertor. But a modern car adds just enough fuel to adjust to whatver the load is, it doesn't work against the convertor unnecessarily at idle the way 1950s- early 1990s cars did.

 

[Kawiguy454]

It never ceases to amaze me that a certain percentage of responses always involve how badly things will go wrong when I knowingly take an action then somehow forget where I'm at and what I'm doing resulting in a catastrophic chain of events. Must be some of you had a nanny growing up to take care of your fails before they happened.

Disclaimer: If you on meds or just stoopid ...don't try this at home it could lead to an epic fail.

Sitting at a light stopped the 1st gear clutch pack is engaged fully and the torque converter is slipping. The fluid temperature rises probably 50 degrees in a minute. If it is stop and go traffic the high temperature will soak in and never go down to normal cruising temp until after you're cruising again. The slipping tq converter is why we put transmission coolers on towing vehicles and race cars.