Can these shifts harm an automatic transmission?

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Originally Posted By: Linctex
There is NO HARM EVER shifting to neutral when stopped.

It is the simple act of engaging and disengaging clutches internally.....
which is EXACTLY what happens every single time an auto trans shifts gears!


If the car is kept in "D" at a stop, isn't the transmission still in 1st gear being held at bay by the brakes? In which case the internal clutches would still be engaged. Wouldn't that be less cycles on the clutches than shifting into neutral, then back to "D."
 
Originally Posted By: Linctex
There is NO HARM EVER shifting to neutral when stopped.

It is the simple act of engaging and disengaging clutches internally.....
which is EXACTLY what happens every single time an auto trans shifts gears!


Simple misunderstanding here. But wildly transmission specific, as they are not all exactly the same in operation, design, or programming...
 
Originally Posted By: 69GTX
Fwiw, back in the days of my coasting down long hills to conserve gas (15 yrs ago) I recall one occurrence where at approx 45-55 mph and starting to climb the next grade I did my shift from "neutral" to "drive." Well, I missed "drive." I somehow found "reverse" probably while being too occupied with what was on the radio. The car bucked a bit, came to a fairly abrupt halt/stalled. I was sure I destroyed the transmission. But, that was one tough '85 Ford LTD 6 cyl. It started fine and off I went. No issues with the transmission right until I sold it a couple years later. Had about 165K miles at that point and the engine had numerous issues and the body had numerous dents.

I sold that car to a young lad in my neighborhood for $50. I could have junked it for more. He was looking for cheap transportation to get him to California, 3000 miles away. I told him he'd be fortunate to make it out of the state. Never did find out how he made out.


my grandfather had the mercury version of that car.plenty of power from that 3.8l v-6, but head gasket problems.
 
Originally Posted By: rooflessVW


If you want to speed up a shift up (or down), give it less or more gas. Don't take it out of gear and try to rev match.

Leave it in gear costing downhill.


Some newer automatic equipped cars are designed to coast in neutral. My 2er does that in Eco Pro mode- but it can be disabled. I believe that some of the Porsches with PDK do it as well.
 
Originally Posted By: MCompact
Originally Posted By: rooflessVW
If you want to speed up a shift up (or down), give it less or more gas. Don't take it out of gear and try to rev match.

Leave it in gear costing downhill.

Some newer automatic equipped cars are designed to coast in neutral. My 2er does that in Eco Pro mode- but it can be disabled. I believe that some of the Porsches with PDK do it as well.

Yes but the car is designed for this purpose. You still leave it in drive.
 
Originally Posted By: clinebarger
I find all those practices odd, The only one I see causing an issue is #4 depending on the design of the transmission......

I'll use a GM 4L80E as an example.......
Putting it neutral at speed will cause all Clutch packs & Bands to release, In turn causing the Direct Drum to take the path of least resistance....Which means the Drum is now overrunning 3 times the RPM that the Output Shaft is turning. The shift back into 3rd will bring the Directs back on & they have to slow the Drum back down to drive shaft speed, This is particularly hard on the Direct Frictions because they have to slow down a 16 pound drum with inadequate/low Line Pressure.

Rev-matching the engine does nothing to help with the Line Pressure issue whether TV Cable, Vacuum Modulated, Or Solenoid controlled because your not loading the engine, TV & Solenoid will add some pressure from throttle input......But it takes little throttle to rev a engine to desired RPM in neutral.

If you need to pass/kick down a gear.....Force a Automatic Detent by gassing it, They're designed to work this way!

Do you have any idea what was happening in my 3spd auto 1995 Neon when I shifted to N going down hills? I always rev matched a little going back into D and it re-engaged pretty smoothly. Over the years I did this 1000's of times, but that trans seemed to be pretty tough as it survived a few track days as well.
The odd time I'll coast in N with the CRV and it seems to re-engage Ok but I don't do it often.
 
Originally Posted By: IndyIan

Do you have any idea what was happening in my 3spd auto 1995 Neon when I shifted to N going down hills? I always rev matched a little going back into D and it re-engaged pretty smoothly. Over the years I did this 1000's of times, but that trans seemed to be pretty tough as it survived a few track days as well.
The odd time I'll coast in N with the CRV and it seems to re-engage Ok but I don't do it often.


Back in the early 1970's we had my Grandmother's 1964 Buick Wildcat (401 ci - 320 hp gross). Now that car was a coasting fool. I recall numerous times in the hills of NJ coasting on the highways at close to 85-90 mph. Since that car had a carburetor it probably got better mpg doing that. Trans was never an issue.
 
I have shifted into N in traffic jams and the like when things are seriously at a stand still. I've seen some folks shut down their engines completely for really bad situations but always worried about being the one person that couldn't get his car started again further aggravating the situation! I think the only harm with #3 is someone honking at you if you're not johnny on the spot to get moving again!
 
Originally Posted By: rooflessVW

Yes but the car is designed for this purpose. You still leave it in drive.


Sorry; wasn't disagreeing with you, just pointing out the technology.
 
Originally Posted By: MCompact
Originally Posted By: rooflessVW
Yes but the car is designed for this purpose. You still leave it in drive.

Sorry; wasn't disagreeing with you, just pointing out the technology.

Sorry if I came across a little short. I have been told this is one of my issues.

It's actually one of my favorite features in modern hybrids; the ability to "sail" on the highway using just the electric motor.
 
Originally Posted By: rooflessVW
Originally Posted By: MCompact
Originally Posted By: rooflessVW
If you want to speed up a shift up (or down), give it less or more gas. Don't take it out of gear and try to rev match.

Leave it in gear costing downhill.

Some newer automatic equipped cars are designed to coast in neutral. My 2er does that in Eco Pro mode- but it can be disabled. I believe that some of the Porsches with PDK do it as well.

Yes but the car is designed for this purpose. You still leave it in drive.



The times I don't want to leave it in Drive is when coming down steep hills...I don't want it to shift back from 3rd to Drive after "tapping the gas." And it will do that as you pick up speed down the hill.

And also on up and down roads/terrain where you might average 35-45 mph in moderate traffic. Rather than having the trans shift back and forth from 3rd to Drive every few hundred yards, just leave it in 3rd until you're back on a clear and open road or highway.
 
People misunderstand most slushboxes all the time.

If the trans is operating correctly there is little to no wear on the friction pieces while engaged in gear. This is also true when at a stop. It is only during a shift even that anything is released and engaged, that is when the wear occurs. Shifting when not needed just makes more events that cause the wear
 
Originally Posted By: SteveSRT8
People misunderstand most slushboxes all the time.

If the trans is operating correctly there is little to no wear on the friction pieces while engaged in gear. This is also true when at a stop. It is only during a shift even that anything is released and engaged, that is when the wear occurs. Shifting when not needed just makes more events that cause the wear


Exactly. The only thing I do a little different with an AT is this. My driveway is on a slight incline pointing toward the house. I back into the driveway. When I pull out of the driveway, I coast a few feet in neutral and then put it in drive with my foot off the brake. I'm probably rolling about 2 mph, it's a bit less shock on the drive train. If I'm on level ground in park, I move the shifter to neutral, foot on the brake, and then to drive with my foot off the brake. Less shock on the drive train again. I've been doing that for as long as I can remember. FTR I'm not giving it any gas, when I shift from neutral to drive, I just don't have my foot on the brake.
 
Originally Posted By: HosteenJorje
Put it in gear, accelerate and forget it. Maybe see a psychotherapist. Even better, see a psychiatrist who will probably put you on medication.


Must be the guy SRT8 was referring too....lol. Your lack of inquisitiveness must be a sight to behold. My wife doesn't think much about the car's automatic transmission either. Not thinking doesn't equal maximum life/optimum performance.

Glad you finally woke up....this thread has only been up for a week. Thanks for your lack of participation.
 
Originally Posted By: demarpaint
Originally Posted By: SteveSRT8
People misunderstand most slushboxes all the time.

If the trans is operating correctly there is little to no wear on the friction pieces while engaged in gear. This is also true when at a stop. It is only during a shift even that anything is released and engaged, that is when the wear occurs. Shifting when not needed just makes more events that cause the wear


Exactly. The only thing I do a little different with an AT is this. My driveway is on a slight incline pointing toward the house. I back into the driveway. When I pull out of the driveway, I coast a few feet in neutral and then put it in drive with my foot off the brake. I'm probably rolling about 2 mph, it's a bit less shock on the drive train. If I'm on level ground in park, I move the shifter to neutral, foot on the brake, and then to drive with my foot off the brake. Less shock on the drive train again. I've been doing that for as long as I can remember. FTR I'm not giving it any gas, when I shift from neutral to drive, I just don't have my foot on the brake.



Thanks you Demarpaint for a thoughtful reply. That's basically what I've been doing and why I asked about it. Sometimes I really wonder about the thoughtless responses often seen around Bitog and other car blogs. I would think the vast majority of car owners would say that anything but shifting with the car fully stopped, AND the brakes on, will do damage/produce more wear on the transmission. Again, it's why I asked.
 
Originally Posted By: 69GTX
Originally Posted By: demarpaint
Originally Posted By: SteveSRT8
People misunderstand most slushboxes all the time.

If the trans is operating correctly there is little to no wear on the friction pieces while engaged in gear. This is also true when at a stop. It is only during a shift even that anything is released and engaged, that is when the wear occurs. Shifting when not needed just makes more events that cause the wear


Exactly. The only thing I do a little different with an AT is this. My driveway is on a slight incline pointing toward the house. I back into the driveway. When I pull out of the driveway, I coast a few feet in neutral and then put it in drive with my foot off the brake. I'm probably rolling about 2 mph, it's a bit less shock on the drive train. If I'm on level ground in park, I move the shifter to neutral, foot on the brake, and then to drive with my foot off the brake. Less shock on the drive train again. I've been doing that for as long as I can remember. FTR I'm not giving it any gas, when I shift from neutral to drive, I just don't have my foot on the brake.



Thanks you Demarpaint for a thoughtful reply. That's basically what I've been doing and why I asked about it. Sometimes I really wonder about the thoughtless responses often seen around Bitog and other car blogs. I would think the vast majority of car owners would say that anything but shifting with the car fully stopped, AND the brakes on, will do damage/produce more wear on the transmission. Again, it's why I asked.



No problem! We're here to ask questions and learn. I'm very easy on my equipment, in my younger days, not as much. I've thrown cars into reverse at speeds that would scare the [censored] out of any sane person, to see what would happen. I did this many decades ago. What I learned was they'd stall and roll forward. Popping them in neutral first and pegging the gas would cause a wheel to spin in the opposite direction and eventually the car will back up. Don't try this at home.

Now I drive easily. I know people who go from drive to reverse, and reverse to drive w/o stopping at slow speeds, common sense tells me it is not good. For the longest possible transmission life, I'd say drive it easy, come to a complete stop before changing directions, [I like to pause in N for a second or two before changing directions] and service the unit. Those are two good places to start. Living in an area where there's little to no traffic, and commutes involve nice traffic free highway conditions would be great too. Unfortunately we aren't all that lucky!
 
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