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Questions tagged [transmission]

These are questions regarding transmissions in general (either manual, automatic or CVT transaxles and their component parts). This tag is not for questions specific to any type of transmission. Instead, use [manual-transmission], [automatic-transmission], or [cvt-transmission] INSTEAD. Use this tag if the question is relevant to multiple types of transmissions.

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97
votes
17answers
240k views

Does Downshifting (Engine Braking) Cause Extra Wear and Tear?

Does the act of downshifting to slow your vehicle down have any negative side affects? I don't downshift more than one or two gears at a time and I let out on the clutch slow enough that I don't rev ...
34
votes
6answers
65k 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 ...
32
votes
6answers
27k views

Why is a motorcycle's neutral between first and second gears?

The gear pattern is selected by clicking a lever with your left foot and is typically laid out as follows: 6th gear (if applicable) 5th gear 4th gear 3rd gear 2nd gear NEUTRAL 1st gear What is ...
29
votes
1answer
29k views

Why does the reverse gear in manual transmission cars sound different

When I got a manual transmission car (2003 Kia Rio) I noticed that it makes a winding sound in the reverse gear. Here is an example video that I found that demonstrates the sound. http://www.youtube....
21
votes
13answers
51k views

Leaving car with automatic transmission in Neutral instead of Park

Can we use Neutral (N on the selector) instead of Park (P) when parking on a flat surface? Is this useful for transmission system? Because every time we put gear on P we must pass through R and will ...
20
votes
11answers
35k views

Need I press clutch pedal while starting my car in neutral?

As I know, clutch pressing and neutral gear both disengage the engine from wheels. So will it matter if I do not press the clutch if I start in neutral?
18
votes
4answers
74k views

Driving in second gear at 65+ mph

I accidentally drove my 2000 Grand Marquis on second gear on the highway. I was going 65 for like 5 minutes and tried to get it to 70mph but the car was shaking, when I realized I put it into regular ...
16
votes
11answers
145k 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
4answers
10k views

Is downshifting on hills harmful for non-trucks? [duplicate]

Possible Duplicate: Does Downshifting (Engine Braking) Cause Extra Wear and Tear? Since the days of taking drivers ed (many years back). I was told that when you encounter a steep or extended ...
16
votes
2answers
72k views

Engine revs high 5th gear manual transmission

What might cause a car with a manual transmission that in 5th gear when given a punch of gas revs to very high rpms – with no power transferred to the wheels (i.e. the tachometer and speed go ...
15
votes
4answers
7k views

Why do 5 and 6-speed transmissions typically need different gear ratios?

My 2013 Subaru WRX has a 5-speed manual, and I long for it to have a 6th gear when cruising on the highway. A friend has a 2012 Subaru STI with a 6-speed manual, and I noticed his car runs through ...
15
votes
5answers
85k views

How difficult is it to rebuild a transmission?

I have a 1984 Toyota Supra that is now exclusively a track car. The last round out we let some less experienced drivers take the wheel and they basically destroyed the transmission. Nothing but 4th ...
14
votes
5answers
263k views

Car shakes when in gear at red light

I bought a '96 Toyota Camry about a month ago. When I first turn the car on and the engine is cold, I can have the car stopped (in gear) and it will not shake. The idle RPMs will be at 1000. After ...
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
6answers
4k views

What would happen if you shifted into reverse while you are going forward?

First, I am talking about manual cars and I know this is considered impossible because of the synchronized gears, but lets suppose that you can manage to shift gears (For example you could shift into ...
13
votes
5answers
191k 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
1answer
8k views

What differences are there between straight cut and helical cut gears?

in formula one, and most other motorsports they use straight cut gears as shown below. in most normal cars you will see helical cut gears as shown below. if both teeth are the same thickness the ...
13
votes
5answers
21k views

What is the life expectancy of a Honda Civic Hybrid Continuously Variable Transmission?

I have a 2006 Honda Civic Hybrid with continuously variable transmission (CVT). At the 90k tuneup, the mechanic added 3.5 quarts of the regular automatic transmission fluid. At 110,000 miles, the ...
12
votes
9answers
11k views

How to add a 7th gear to a car to enhance fuel economy?

Let's say there's a 6-Gear manual transmission car, whose 6th gear equals 2000 rpm at 100 km/h (~60 mph). How can one theoretically add a 7th gear that can maintain the same speed at 1400 rpm in ...
12
votes
5answers
41k views

2003 Chevrolet Impala - Jerks after Stopping

I have a 2003 chevy impala. When I hit the gas (whether it be a light tap or hit it pretty hard), my car kind of waits a second, jerks and then takes off (revs go kinda high when it's waiting). To ...
12
votes
2answers
5k views

Car won't come out of reverse gear unless rolling

I have a 1989 Nissan Skyline R31 and when I put it into reverse, it will refuse to come back out of gear. The clutch was changed a few thousand km's ago and has had this problem recently. The only ...
11
votes
5answers
2k views

Do cars go from Drive to Neutral on their own?

While stopped at a railroad crossing in my A/T Honda CRV with my car in Drive and my foot on the brake; does my car eventually go into Neutral on its own if I'm there for while?
11
votes
4answers
79k views

Optimal RPM range for manual transmission

Are there optimal RPM ranges for different vehicles? I've been told it's better for the engine to drive at slightly higher RPMs (e.g. 2500-3000 for my Tacoma) than low (1000-1500). I understand a ...
11
votes
1answer
2k views

Why don't cars use Sequential gearboxes?

I have always felt that the Sequential Gearbox configuration is much much faster than a ordinary gearbox used in cars. Why is this design used ? Any advantages? Note: I am aware that racing cars(...
10
votes
9answers
45k 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
4answers
26k 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
1answer
2k views

How does Audi Crown Gear Center Differential work?

I'm trying to understand how the engagement of the clutches is varied. I see the power is transmitted through the center input shaft and is transmitted through the four pinion gears, but I don't ...
9
votes
5answers
107k views

Shift “Grinding” Issue?

Lately I've been noticing a grinding/resisting force and sound when I shift from first to second gear in my 2003 Jetta GLI. It is ruining driving for me because every time I shift from first to second ...
9
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 ...
9
votes
2answers
3k views

Why do hybrids still use mechanical transmission?

One of the comments on this question reminded me of something I've been wondering for a while. Given that engines get the best efficiency at peak torque, why do most hybrid cars still use a mechanical ...
9
votes
3answers
652 views

Switching gears without clutch

I drove manual car for a long time but never tried to switch gears without clutch. Question: given that clutch-less shift is executed properly, does it take a toll on transmission in any way? For ...
9
votes
4answers
2k views

What problems may occur if clutch is not used?

I was curious about what problems may arise if clutch is not used when shifting gears. Are the problems similar for both cars and bikes?
9
votes
2answers
34k views

Motorcycle transmission occasionally pops out of gear

I'm having an issue where the transmission will occasionally downshift by itself during a fast acceleration. I have a 2005 Suzuki Vstrom 650 and it's been a great bike so far. At pretty high revs, 9k-...
9
votes
2answers
2k views

Skipping gears when downshifting

Is it bad to skip gears when downshifting manually, e.g. from 4th directly down to 2nd etc?
9
votes
1answer
1k views

Why did manufacturers go to other than 1:1 transmission ratios?

While reading this question it came to mind: Why did manufacturers start building transmissions without a 1:1 ratio? In the older transmission you'd see the 1:1 ratio all the time, either as the ...
9
votes
0answers
390 views

Torque convertor shudder? [closed]

I drive a 2011 GMC Sierra 2500HD ex-cab 2wheel drive with a 6.0 gas engine and a six speed 6L90 automatic transmission. I have started noticing what I believe is called "shudder" from my tranny under ...
8
votes
4answers
785 views

Why aren’t drive chains completely taut?

I don’t understand why roller drive chains in motorcycles have some degree of slack (around 1 inch movement) in them? What’s wrong with having a completely taut chain with no slack? Also, does the ...
8
votes
3answers
1k views

How is it possible for the crankshaft RPM to not directly correlate to the driveshaft RPM?

While I was in my automatic car, I was on a steep upwards slope and I took my foot off of the brake and put it onto the gas pedal. My car first slid backwards, but as the engine applied power to the ...
8
votes
3answers
12k views

Engine braking with an automatic transmission

For reference, I've reviewed these three questions: Manually shifting an automatic transmission? Does Downshifting (Engine Braking) Cause Extra Wear and Tear? Is engine braking harmful? I drive a (...
8
votes
1answer
2k views

Is it bad to shift into reverse while still moving forwards?

I often put my manual car into reverse while still moving forwards. I do it at less than 10mph. However, sometimes the gears crunch. Am I doing any damage by doing this? Why do the gears crunch? I ...
8
votes
2answers
23k views

Clutch pedal no longer provides resistance, clutch won't disengage, what likely failed?

A little background information: Car: 1993 Ford Mustang LX [2.3L I4], 5-speed T5 transmission. I bought the car a few months ago, according to the previous owner the clutch was replaced fairly ...
8
votes
1answer
1k views

How does the Koenigsegg Regera work?

The Koenigsegg Regera is Koenigsegg's newest car, and is a hybrid. However, unlike other "hypercars," like the Holy Trinity, the Koenigsegg doesn't have a gearbox. I'm assuming that it uses some sum ...
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
2answers
1k views

Why can't the 3rd generation Mazda rx7 safely coast downhill in neutral?

The manual for the 3rd generation Mazda rx7 says not to roll downhill without the engine engaged, because the exhaust can overheat. Unfortunately, the manual does not explain the mechanism by which ...
8
votes
1answer
9k views

Should I change transmission fluid if it's black?

I bought a vehicle couple of weeks ago. I checked the transmission fluid today, and noticed it was black. Should I be worried and immediately go change it? Part of me wants to get it changed since I ...
8
votes
1answer
813 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
2answers
27k views

What does it mean to have a stiff first gear?

This problem is a small one and it can only occur with manual cars, but I have been curious to find out more about it for a while now. Sometimes, when the car is attempting to pull away from a ...
8
votes
2answers
28k views

Something Blocking Stick Going Into First Gear

I seem to be having a bit of trouble with the first gear of a 2004 Opel Corsa. I have pulled off the gear stick cover and cant see anything stuck so it must be something that is more internal. When i ...
8
votes
1answer
148k 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
67 views

I own a 1989 Mercedes 560sec that has rpm surges for no real reason

It happens once or twice a month, I could be doing 60 mph, and its almost redlining at 5000 rpm!. Once the vehicle gets to normal operating temperature, and I turn it off for a few minutes and turn it ...