25
votes
Accepted
Does a Car Keep Moving If Neither Accelerator, Nor Brake Is Pressed?
In short, find a better driving instructor and, if possible, learn to drive a car with manual transmission.
The long (still simplified) answer:
Does the accelerator control and ensure gas is flowing ...
- 2,280
24
votes
Accepted
How do the latest automatic transmissions match the efficiencies of manual gearboxes?
Traditionally...
The major drawbacks of automatic transmissions were:
parasitic losses in the torque converter, something which manual transmissions don't have.
fewer gears, so a given engine was ...
- 39.2k
21
votes
Why is towing a manual transmission car, in neutral, with the drive wheels on the ground, considered safe?
Manual transmissions (most, but not all) lubricate not through a pump, but through the action of the gears and secondarily through the level of the transmission fluid itself. In some transmissions, ...
- 160k
20
votes
How do the latest automatic transmissions match the efficiencies of manual gearboxes?
A lot of new automatic transmissions (e.g. Volkswagen DSG) arent actually auto transmissions, at least not in the traditional sense. They have a normal computer-controlled dry clutch (well two ...
- 1,350
14
votes
Why do you use the "park" gear to park a car and not only the handbrake?
Putting the transmission into "Park" engages the "parking pawl" - essentially a metal pin that locks the output shaft of transmission (and thus the driven wheels) in place.
As to why it exists - it ...
- 10.3k
12
votes
Accepted
Why is the ATF Level checked with the engine running?
There are two main things about tranny fluid:
Transmission fluid is checked when it's hot (up to running temperature). As the fluid gets up to temperature it expands. If the fluid is cold, it won't ...
- 160k
12
votes
Accepted
Found a 10 mm nut in the transmission fluid
Okay. Lot's of research, long story, found the answer, don't like it.
Overall design of the Nissan B13: one of the things that always impressed me about this vehicle is that it seems to have been ...
- 12.2k
11
votes
Accepted
Mysterious "5th" Gear on a 4-Speed Automatic?
The transmission has a lock up torque converter.
The torque converter sits between the engine and transmission. It is kind of like a clutch on a manual transmission car. When the engine is idle, it ...
- 8,403
11
votes
Does a Car Keep Moving If Neither Accelerator, Nor Brake Is Pressed?
Note, most of these answers are very specific to an automatic transmission and also a gasoline (petrol) engine -
The position of the throttle generally controls the volume of air allowed to enter the ...
- 25.5k
10
votes
Accepted
How Does a Quick Shifter work in a motorcycle
Why the Quick-Shifter?
Since these are called quick-shifters we'll dub slow-shifting the traditional way of shifting gear. When you slow-shift you usually close the throttle, disengage the clutch, ...
- 1,765
10
votes
Accepted
Bump on the floor in the back of sedans
The hump provides longitudinal rigidity in the unibody. The fact that it also provides a place to route the exhaust is a bonus.
Notice that modern CAD-designed vehicles have much less of an obvious ...
- 1,733
10
votes
Switch from N to D without brake
Should be no problem at all.
The manual is being overly cautious, since the usual case for shifting from neutral into drive is when you're stopped hold the brake will prevent the car from starting to ...
- 14.5k
9
votes
Looking at buying a 1997 Toyota Camry XLE V6 with dark colored ATF, mistake?
95% chance it's just normal wear. The vast majority of car manufacturers recommend an ATF change between 30,000 and 100,000 miles. So if the owner hasn't serviced it in a bit, the brown colour would ...
- 5,235
9
votes
Would not allowing my vehicle to downshift uphill be fuel efficient?
The primary reason to down shift is more power.
The 2 things effecting your gas mileage here are throttle position and RPM. As long as you can stay in 8th at less than half throttle, I would stay ...
- 8,403
9
votes
Accepted
Switch from N to D without brake
No harm done
On contemporary vehicles there is no direct mechanical linkage between the gear selector and the automatic transmission.
Instead, the gear selector selects a "state" (e.g. N, D, R, 1, 2....
- 39.2k
9
votes
Accepted
Chevrolet 2008 Suburban, I removed the transmission fluid pan by mistake. Can I just put it back on and refill fluid?
While it's inconvenient, there's no reason you can't resolve this yourself.
The transmission fluid pan has a single-use gasket on it, if you just bolt it back on you run the risk of fluid leaks, which ...
- 17.1k
8
votes
Bump on the floor in the back of sedans
Anyone can feel free to disagree with me since I'm not 100% on this, but I believe those bumps are placed into the design in order to give the exhaust system a little more breathing room.
Note the ...
- 1,958
8
votes
Bump on the floor in the back of sedans
I don't think the hump is there just for the exhaust, although as was pointed out in the comment it adds ground clearance which is a nice thing. The "transmission hump" (in honor of rear wheel drive ...
- 14.5k
8
votes
Accepted
Would not allowing my vehicle to downshift uphill be fuel efficient?
The power output of an engine is determined by how fast it can capture the energy released from fuel. There is an optimal range for that fuel-to-torque conversion, before and after which efficiency ...
8
votes
Why is towing a manual transmission car, in neutral, with the drive wheels on the ground, considered safe?
Because, in a manual gearbox (those that I am aware of) the method of lubrication is by splash as the layshaft sits in the oil, so there is no engine driven pump connected to the input shaft.
Same ...
- 34.7k
7
votes
Would not allowing my vehicle to downshift uphill be fuel efficient?
On flat ground, you can go by the general rule: the higher the gear the less fuel you burn. You also get less power, but it is more efficient, and it isn't bad for the engine provided it isn't ...
- 5,235
7
votes
Idling with no transmission fluid
I don't know what year your vehicle is (240 Volvo's I think were primarily in the 80s and 90s), but most vehicles of that era with automatic transmissions have the main pump being directly driven off ...
- 160k
6
votes
Manually shifting an automatic transmission?
I've rebuilt a few transmissions (actually a lot of transmissions LOL) and no, manually shifting is just fine. All your doing is replacing the TCU with your own shifts. So your just fine manually ...
- 71
6
votes
Any truth to the "myth" about changing transmission fluid in older vehicles?
There is a lot of debate about late ATF changes killing transmissions. To find the real answer you would need a statistically significant number of vehicles for each transmission, and a same-sized ...
- 2,169
6
votes
Push start a car with automatic transmission
Automatic transmissions originally had a feature that allowed push starting, a rear pump in addition to the front pump. If the car was rolling the rear pump would provide pressure even if the engine ...
- 61
6
votes
Looking at buying a 1997 Toyota Camry XLE V6 with dark colored ATF, mistake?
You're getting a bit ahead of yourself thinking a about a transmission swap in a 1200 dollar car. Dark transmission fluid is completely normal at that mileage. It probably has never been changed, but ...
- 1,742
6
votes
How do the latest automatic transmissions match the efficiencies of manual gearboxes?
With a greater number of gears in the autobox and with a lock-up function called more frequently for the fluid flywheel.
Then add a better computer based control system for moving between gears : ...
- 34.7k
6
votes
Accepted
Can i use Honda CVT fluid in a Honda ATF transmission?
No, you should not under any circumstances be adding the incorrect fluid to a transmission. If the transmission in question calls for ATF use ATF. Likewise, if it calls for CVT fluid use CVT fluid. ...
- 643
6
votes
Does a Car Keep Moving If Neither Accelerator, Nor Brake Is Pressed?
Does the accelerator control and ensure gas is flowing through the engine? The harder I press, the more gas flows in and the faster is the engine RPM. Is my mental model correct? Also, if this is the ...
- 183
6
votes
Accepted
How does the ATF flow between torque converter and the transmission?
In the part of the torque converter which is attached to the transmission, there's a big hole. Fluid travels in and out of it through this hole.
The front of the transmission looks something like the ...
- 160k
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