Questions tagged [automatic-transmission]

Questions regarding automatic gearboxes, and associated parts such as torque converters

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40
votes
3answers
75k views

Is there a way to put Prius with dead battery into neutral?

I own a 2010 Prius. It has a dead battery, front facing forward in my garage. I do not have long enough jumper cables. I’ve searched the Internet. Did Toyota really create a car that cannot be put ...
34
votes
6answers
63k views

Why doesn't anyone ever repair an automatic transmission?

I am old enough to have had about four transmission failures spaced over about 40 years and at no time did any mechanic ever offer to “fix” it; the only diagnosis has been a complete rebuild. This is ...
34
votes
2answers
45k views

What's the Purpose of Park on an Automatic Transmission?

When one wants to park a manual transmission (MTX) vehicle, one puts it in neutral, and engages the emergency / parking brake. With an ATX vehicle, the practice I've learned is to put it in Park, and ...
25
votes
9answers
352k views

What's the point of the D3 gear in an automatic transmission?

My Honda Civic has a D gear and a D3, which apparently prevents it from going into 4th. Why would I want to do this? What is it good for? Does it make my fuel efficiency better or worse? Does it ...
22
votes
3answers
5k views

How do the latest automatic transmissions match the efficiencies of manual gearboxes?

Most people know that for old or even somewhat old cars, manual transmissions are more efficient. Recently automatic cars have become almost as efficient or even as efficient as manuals. I was ...
22
votes
2answers
20k views

Why doesn't the engine stall out when you come to a stop with an automatic transmission?

When you come to a stop with a manual transmission you have to push the clutch in or take it out of gear to keep the engine from stalling out. What keeps the engine from stalling in an automatic ...
21
votes
2answers
18k views

Why is towing a manual transmission car, in neutral, with the drive wheels on the ground, considered safe?

It is clear that cars with automatic transmissions cannot be towed with any drive wheels on the ground, engine off, in neutral, because the torque converter powers the lubrication pump for the ...
19
votes
7answers
5k views

Are manual transmission cars disappearing? [closed]

You don't have to be an expert to notice that over time, the percentage of manual transmission cars has lowered. Automatic cars are not only more popular, but more comfortable, easier to use and ...
19
votes
3answers
9k views

shifting stops when critically low on gas

I have a 1999 Dodge Dakota. It is a V6, 3.9 Liter, auto transmission. I have a weird problem that no one has been able to answer for me. HOW I CAME TO REALIZE THE PROBLEM: One day I was driving ...
17
votes
1answer
26k views

What is a governor and what is it used for?

I was watching a classic car restoration program on YouTube in which they were working on a '50s Cadillac with an automatic transmission. The mechanic in the video diagnosed a transmission glitch as ...
17
votes
4answers
117k views

Push start a car with automatic transmission

Is it possible to push start a car with automatic transmission? Use case: Let's say the battery is dead or you have a bad starter. I know this can be done on manual cars by putting the car in to gear ...
16
votes
11answers
140k views

Use of Neutral Gear in Automatic Transmission

I am new to driving A/T cars and I am trying to understand the use of Neutral(N) gear. Should I shift my gear from D to N when my car comes to a complete halt on a red light or somewhere else? As per ...
16
votes
6answers
73k views

Can coasting in neutral damage an automatic transmission?

When I drove a manual transmission, I got in the habit of shifting to neutral on long, shallow grades to save fuel. Now I'm driving an automatic (specifically, a recent Corolla) and still doing it. ...
15
votes
6answers
67k views

Does putting an automatic car into neutral at stop lights significantly harm the transmission?

I drive a 2013 Mazda 3, in case that makes any difference to the answer. There seems to be a few discussions on the web which indicate that putting an automatic car into neutral does not ...
15
votes
1answer
22k views

How does an automatic gearbox know when to change gear?

As the title suggests, how does an automatic gearbox know when to change gear? For example, how does the autobox know to shift down when you hit a gradient? How does it know to shift up at 2000 rpm ...
14
votes
5answers
78k views

Switching from Reverse to Drive - always stop completely?

I've been told by a couple people that it's really bad for a car to be shifted from Reverse to Drive while the car is still moving backwards. Is this true? In my experience: On automatic cars, this ...
13
votes
11answers
44k views

Any truth to the “myth” about changing transmission fluid in older vehicles?

I have had people give me anecdotal stories (friend of a friend type thing) about changing the transmission fluid in vehicles with 150,000+ miles, especially those that haven't had regular ...
13
votes
3answers
4k views

How does the transmission not strip itself when applying the brake?

Quick question bugging me: Obviously the car moves forward when neither applying the brake nor the accelerator. How does this not damage the transmission when the brake is pressed? I first ...
13
votes
5answers
175k views

Automatic transmission: Is shifting to neutral while approaching stops bad?

This is not with the intention of saving fuel (as I have seen many answers assuming savings in fuel while doing this). But I have this habit of putting the vehicle into neutral before approaching ...
13
votes
4answers
24k views

Does engine braking an automatic wear out the transmission?

My question is a variation on these two: Engine braking with an automatic transmission What are the “1” and “2” or “L” gears used for on an automatic? I recently bought an automatic transmission ...
12
votes
4answers
80k views

What disadvantages a car with 4-speed transmission have compared to 5, 6 or 7 speed with similar engine?

This seemed to be most relevant site to ask my question. I am planning to purchase a new car and my shortlisted car has 4 speed automatic and 1.6 litre engine. The thing that worries me is that it ...
11
votes
4answers
55k views

What are the “1” and “2” or “L” gears used for on an automatic?

In a car with an automatic transmission, we are normally greeted by the acronym PRNDL, or in some cases (older cars) PRND21. I know that the L, 1, or 2 will cause the transmission to stay in a (L)...
11
votes
2answers
24k views

How exactly does Sport Mode work in an automatic Subaru Outback?

I have 2008 Subaru Outback (160K miles) with an automatic transmission and have been curious about the Sport Mode that can be shifted into. I read in the car's manual that it increases pickup and is ...
11
votes
2answers
2k views

I'm stupid and added tranny fluid to my coolant tank. What can I expect?

Title pretty much says it all. I'm a computer guy, not a car guy. I saw a bunch of red fluid coming out of my vehcile, assumed it was tranny fluid. Turns out it was antifreeze. This means the bit of ...
11
votes
2answers
2k views

Mysterious “5th” Gear on a 4-Speed Automatic?

My 1998 Honda Civic LX is equipped with the 4-speed automatic transmission. Before I looked this up, I decided to count the number of upshifts from a stop, and I counted four, not three. This mystery "...
10
votes
9answers
43k views

Durability of automatic transmission boxes versus durability of manual transmission boxes? Their lifetimes?

My friend is against cars with automatic transmission because he thinks that they break easily and that their repairing cost a lot. He thinks that it is impossible to maintain an automatic ...
10
votes
3answers
25k views

How Does a Quick Shifter work in a motorcycle

I have often seen motorcycles like the BMW S100RR and the famous Ducati Panigale with Quick Shifter technology which allows seamless gear changes. I want to know how these things work mechanically ...
10
votes
3answers
25k views

Why is the ATF Level checked with the engine running?

I didn't realize until recently that the ATF level is supposed to be checked while the engine is running, unlike the engine oil level which you're supposed to check at least five minutes after ...
10
votes
1answer
976 views

Found a 10 mm nut in the transmission fluid

I was draining the fluid out of the automatic transmission of a '94 Sentra with a RL4F03A tranmission. While I was removing the magnets, one of them was holding onto a 10 mm hex nut. It was clean, not ...
9
votes
3answers
4k views

Bump on the floor in the back of sedans

I can close this if it's a dup but my Google-fu didn't find a satisfactory answer. In the middle of the floor of some older automatic transmission sedans, there is a bump (my old 4 dr 2005 Accord, 4 ...
9
votes
2answers
5k views

Switch from N to D without brake

Will it cause any damage to the engine/transmission if one switches from N to D without pressing the brake pedal? I was driving at about 40 mph when I accidentally switched to N. Then after a while I ...
9
votes
4answers
76k views

Can I use a Dexron III automatic transmission/power steering fluid where a Dexron II is required ?

more generally speaking are 'higher Dexron numbers' also fulfilling the specifications of the lower number fluids ?
9
votes
1answer
3k views

How can I be sure of the reading on my automatic transmission fluid dipstick?

This may seem like a silly question. I've been trying to read the dipstick for my automatic transmission fluid but am having a very difficult time determining the level. The fluid is very light and ...
9
votes
1answer
2k views

How to Detect a Bad Transmission When Buying a High Mileage Vehicle

Rebuilding a transmission is one of the most expensive things that can be done on a car and I've been told it's one of the main reasons people dump cars other than timing belt issues. I've read ...
9
votes
1answer
4k views

2005 Mazda 3 at warning light at cold start ups

I've noticed recently that my mazda 3 on cold starts would show the at warning light. When I start it, it normally flashes it for a few seconds then disappears. Then when I pull it out of the garage, ...
9
votes
1answer
245 views

Severe Noise Under Acceleration from a Stop or Slow Speed

EDIT March 9, 2016 So I took the car to a guy who specializes in ATX gears, and he felt that it's not a tranny problem. Got a second opinion from a Chevy tech who concurred. So due to that and the ...
8
votes
3answers
2k views

Would not allowing my vehicle to downshift uphill be fuel efficient?

Would putting my car in Sport and leaving the transmission in 8th gear at highway speeds (using cruise) be more fuel efficient than leaving it in drive with full auto? I just noticed that while in ...
8
votes
2answers
4k views

Do Manual transmission cars perform better than Automatic transmission?

I'm stuck between choosing a car available in both automatic transmission (CVT) and Manual transmission (6 speed). I wanted to know which one will perform better in the following aspects (considering ...
8
votes
6answers
7k views

Does switching to neutral on an automatic transmission improve braking for immediate stopping?

I've been told that when needing to brake quickly, throwing the gear into neutral on an automatic transmission actually allows for better/quicker braking. I understand how things work pretty well but ...
8
votes
3answers
115k views

Does towing an automatic transmision car in neutal with engine not running will damage it?

My daughter had a friend tow her 1996 chevy. automatic transmission without engine running while in "N" SLOWLY for probably 7 or 8 miles distance. Do you think she has damaged the transmission? The ...
8
votes
4answers
8k views

Should I change automatic transmission fluid JUST because it's brown?

About a year ago... I bought a used 2006 Hyundai Elantra with an automatic transmission and about 70k miles on it. Before buying it, I had it checked out by a mechanic who said it looked good. ...
8
votes
1answer
800 views

How come gears don’t normally change in an automatic car?

I know that there is a similar question here, and another one here that asks when an automatic gearbox knows how to change gear, but I want to know exactly how it does that. It was brought to my ...
8
votes
1answer
385 views

What is the Connection Between Failing Torque Converters and Vibration?

When trying to determine the source of vibrations at idle in my 98 Mazda 626 GF 2L one thing I've found mentioned by many people is a potentially worn out / failing torque converter. However, when ...
8
votes
1answer
392 views

So I goofed… added fuel cleaner to transmission.

So... as the title says. I accidentally added fuel cleaner to my transmission, which is currently leaking (meant to add stop leak as a temp fix if it worked). I grabbed the wrong bottle and didn’t ...
8
votes
3answers
22k views

Engine tap/knock/noise within a few seconds of starting

1998 I6 - 4.0L All stock ~175,300 mi 13.8 mpg - mostly city A few months ago, I began to hear a noise that sounds similar to a diesel engine, which begins a few seconds after starting the cold engine....
8
votes
1answer
141k views

Why am I not moving after starting car and shifting to Drive?

So I have had this issue for the last couple months where when I first start the car, shifting to Drive (automatic transmission) doesn't do anything. Pressing the gas only revs the engine, as if in ...
8
votes
1answer
1k views

Engagement delay when shifting from neutral to drive or reverse

My 2001 VW Eurovan (T4) has automatic transmission and about 160k miles on the clock. When I use the transmission selector to move from N to D or from N to R, there is a noticeable delay until I feel ...
8
votes
1answer
69k views

My rpms are going high and my mph take a minute to go higher on my GMC Yukon

When I put my truck in drive and step on the gas the RPM's go up to 3,000 but my MPH will stay at 10-15 When I let go of the gas a little bit I can feel the truck kind of pull and the RPM's will go ...
7
votes
9answers
102k views

Strong vibrations when idling even after replacing engine mounts (automatic transmission)

I have a '93 Acura Integra with automatic transmission. Ever since I got it some time ago the car has been vibrating a lot when stopped at a light, for example. The vibration is worse when in gear ...
7
votes
1answer
935 views

What should one do to reduce the HP lost at the wheels on an automatic transmission?

I have a 1990 Toyota Supra Turbo 4 speed auto. I've done some research about automatic transmissions and manual transmissions and what are the positives and negatives of each. (For example, MT is said ...