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

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35
votes
3answers
34k 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 ...
26
votes
6answers
13k 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 ...
24
votes
1answer
4k 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 ...
22
votes
9answers
147k 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 ...
18
votes
2answers
11k 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 ...
17
votes
7answers
3k 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 ...
16
votes
4answers
2k 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 ...
14
votes
1answer
2k 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 ...
12
votes
1answer
10k 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 for example, also how does it know to shift ...
11
votes
4answers
2k 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 ...
11
votes
3answers
23k 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 ...
10
votes
2answers
1k 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 ...
10
votes
5answers
35k 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. ...
10
votes
3answers
1k 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 ...
9
votes
11answers
55k 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 ...
9
votes
3answers
30k 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 ...
9
votes
1answer
148 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, ...
8
votes
4answers
2k 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)...
8
votes
3answers
836 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 ...
8
votes
1answer
788 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 ...
8
votes
4answers
28k 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 ...
8
votes
2answers
382 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 ...
8
votes
1answer
56 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
2answers
13k 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 ...
8
votes
0answers
103 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 ...
7
votes
2answers
169 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 ...
7
votes
6answers
46k 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
209 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 ...
7
votes
4answers
33k 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 ?
7
votes
2answers
155 views

Normal Operating Temp for an Automatic Transmission

While I was able to find information on testing the ATF temperature sensor in the GF4A-EL manual I've got: I was unable to find any info on the normal operating temperature of the transmission. I'...
7
votes
1answer
2k 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 ...
7
votes
1answer
139 views

Will increasing line pressure increase torque capacity?

I was wondering if one were to increase the line pressure sent to the clutch packs/bands on an A/T would that increase the torque capacity of said transmission? I figure it would because it would ...
7
votes
1answer
107 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 ...
7
votes
1answer
73 views

What could cause high RPMs but no power?

I have a 2006 ford fusion and lately it works fine if I lightly press on the gas. If I press on the gas with full force though it will rev up the RPM's but there will be no power and my car won't ...
7
votes
1answer
53 views

How Does Being in Drive Disable the Starter on an ATX Vehicle?

Being used to driving manual transmissions, I occasionally forget to put my ATX in park when I shut off the vehicle ( I'm getting better ). Today I did that without realizing it, and when I went to ...
7
votes
1answer
63 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
1answer
136 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 ...
6
votes
4answers
8k 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 ...
6
votes
5answers
4k 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 ...
6
votes
2answers
2k views

How hot is “HOT” on a transmission fluid (ATF) dip stick?

I want to add some fluid additive (Lucas) to my transmission, but I don't want to overfill it. The dipstick has add, warm, and hot for measuring. So how hot is the hot level? My temperature gauge ...
6
votes
2answers
3k views

What is the difference between an automatic and an AMT

I have seen many recent car launches in my home country which claim to have something called as an AMT or Automated Manual Transmission. I am curious to know how is this different from a traditional ...
6
votes
3answers
3k views

What determines when an automatic transmission shifts?

I'm working on developing an automatic bicycle (mostly microcontroller based) and I'd presume I'd be shifting in a similar way to a car. So my question is, what factors does the transmission take into ...
6
votes
3answers
207 views

Optimal acceleration for automatic transmission? [closed]

In a car with automatic transmission, what's the best way to accelerate so as to minimize fuel consumption? Assume I'm not going to change the gears manually. Note that I'm also considering non-flat ...
6
votes
1answer
167 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 ...
6
votes
1answer
40 views

1998 lincoln continental with fluctuating idle when put in gear only (drive/reverse)

I have a 1998 Lincoln Continental. It has 124k miles on it. The history of the transmission maintenance are as follows: Fluid and filter was changed at 29k miles Fluid was flushed at 86k miles Fluid ...
6
votes
2answers
54 views

Will a Slight Overfill Harm an Automatic Transmission

I flushed my transmission recently, and I overfilled it slightly, maybe by a 1/2 liter on a transmission that takes about 8 liters. When cold, the fluid is a little over the cold mark, but not up to ...
6
votes
1answer
68 views

2000 Celica engine dies or shakes when I pump gas

I have a 2000 Toyota Celica. At first it used to slip gears and then I had a mechanic check it out. He said its a solenoid in the transmission which he changed. The car sputters sometimes when at ...
6
votes
1answer
305 views

Excessive Vibrations in Drive when holding down the brakes

I'm working on a 98 Mazda 626 GF 2L with an automatic transmission. While I'm used to driving manuals, I would say that the amount of vibration when sitting stopped in drive with the brake on seems ...
6
votes
1answer
61 views

Transmission disengages itself

Seems like my car disengage itself from drive to neutral while in motion. I drive a 2004 Honda Accord. When in drive and in motion, the car starts slowing down even with my foot on accelerator. It ...
6
votes
0answers
57 views

Th400 Transmission help

I pulled my Th400 out of my K20 Chevy and I'm in the middle of rebuilding it and I was resembling it and when I went to put the completed gear train assembly in it and the center support assembly gets ...