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31

Most of the time when you drive, you're putting a load (and causing wear) on what I'm going to call the "forward" face of each tooth on each gear in your drivetrain. The front of a tooth on the crankshaft pushes against the back of a tooth on the next gear in line, which pushes the next gear, etc. When you use "engine braking", all you are doing is ...


28

In manual transmissions, the reverse gears use a different type of gear teeth than forward gears. Forward gears are helical gears, which have teeth that are pointed at an angle. When the gears rotate, most of the load is evenly spread due to the angles. Reverse gears are cut into spurs, which don't absorb the load quite so well. As a result, there is ...


12

If you downshift into a gear at a RPM that is within the norm of driving then no, no harm done. When you downshift what is slowing you down is actually the compression stroke and is recommended over hard braking. Like another said, it is a bit of a mix of the two but engine braking is ok as long as the engine stays under redline, so do not go from 5th to ...


12

tl,dr: The short answer is no, with caveats. The longer answer starts with "well, you can kill your car with anything if you try hard enough." Let's use specific examples of when you should use your transmission for engine braking: Waimea Canyon or Mount Washington. In either case, you are descending thousands of vertical feet at significant grades. If ...


12

This is one of those things which are easier said than done. To start with, let me show you a picture of a four speed transmission which has been blown apart: All of those hundreds of parts go through the front end of the transmission. If a single part is bad (which it usually is not the case), you have to pull all of this apart in order to diagnose and ...


11

It's definitely not great. The redline is there for a reason. That shaking was likely the engine speed limiter looking at the RPMs and saying, "yes, that's high enough." The speed limiter can be either an ignition cutoff or a fuel cutoff - both will make the car feel very shaky. The most common bad consequence of an overspeed condition when the engine ...


10

I'm a driver trainer/examiner and most of the time you rarely need heavy braking in traffic. If you drive calmly, allow plenty of distance between you and the vehicle in front (even at low speed)) and just take your foot of the accelerator early you avoid stopping and starting. If you let the car slow down and use the gear until it is no longer appropriate ...


10

It's not something I've ever attempted, but I know people who have... The innards involve a lot of small springs, shims, etc (mainly in the synchros), and these can often have a habit of flying off when released! It is something that should only be attempted in a decent, clean workshop/garage so you can keep track of all the bits as you take it apart, and ...


9

Which would you rather change - your brake pads or your clutch? By downshifting to decelerate you are trading wear on your brake pads for wear on your clutch (among other things). Brake pads are much cheaper and easier to replace than a clutch. Personally, having done both, I'd rather do 50 brake jobs before I'd do one clutch job.


9

It is straightforward to do this without any wear to your synchromesh, but it takes a lot of practice, especially when downshifting as you need to match revs accurately. Learning to heel and toe correctly will help you a lot here! You should never need to race the engine, as you should be using the same rev range as you would normally driving the car!


9

If the RPM rises without a corresponding change in velocity in a vehicle with a manual transmission you've got a slipping clutch.


8

It sounds like the clutch is worn out... You can usually tell by gradually applying the gas in the top gear, probably around 2,500 RPM, and the car should accelerate a little bit, but at some point as you press the gas further and further down, you will feel it release and the revolutions will shoot way up without road speed increasing. It basically feels ...


8

If you match revs correctly you should be able to change gear with no ill effects at all. The challenge is of course to match revs. This is pretty easy when accelerating, but when decelerating you'll need to use the accelerator to bump the engine revs up to match. Google for heel-and-toe (this also helps make for faster downshifts when using the clutch) ...


8

I have heard that most modern cars have rev limiters which prevent damage - is this just to prevent damage to the engine, transmission or both? The rev limiter is there to protect the engine, often to prevent problems caused by the transmission (or the human operator's use thereof). Would that help in this situation? Yes, it would but no, it ...


8

For general driving, you can leave the car in drive. It doesn't damage the transmission leaving it in drive while stationary at the lights - although you don't want to be doing silly things like revving the engine while holding the brakes on. In an automatic car, you don't really use neutral. It is a step on the way to selecting Park, which means that the ...


7

You probably did no immediate damage. Most cars have an electronic limiter that keep the engine RPM from going into the redline, which could cause a blown engine. However, if you kept doing that, your engine would wear out a lot faster.


7

More details of the vehicle in question would be helpful to be sure. However, from personal experience, my guess would be that the shakes are not solely due to the engine being run at high RPM. The Mercury Grand Marquis is equipped with a 4.6L Modular V8 engine and 4R70W automatic transmission, similar to many other products of the Ford Motor Company. ...


7

What follows is not a mechanical fix. That said, I think you are going to have to solve this as a people problem first. Based on the answers in the comments, I would recommend the following: Collect your maintenance records. Collect your warranty documentation, especially the 100K mile warranty. Write a short script for yourself: "I baby my car. The ...


7

The main purpose of neutral on an automatic is for towing or pushing the car. Obviously you can't push it with the transmission in park, and if you tow it with the transmission in gear or in park and the drive wheels are in contact with the ground, you'll ruin your transmission or your tires or both. I'm sure there are some other uses too, but they're ...


7

The first thing to check is the shifter linkage. If it uses a cable the cable my be frayed on the inside of the casing causing the friction. You may also have some other part of the linkage binding up, but my money is on the cable itself. It doesn't seem likely that it would be an internal transmission problem.


6

Donovan's is the only answer that has any truth in it. Downshifting and engine braking will have NO effect on the clutch, as you don't slip the clutch it doesn't wear out the engine, as you use the compression stroke and it is far better on tyres and handling as any advanced driving instructor would tell you. It is just more difficult, as you need to ...


6

First thing I'd check is that it's got the AWD driveline - there should be a driveshaft from the gearbox in the front connecting to a diff at the rear "axle", plus driveshafts from each rear wheel to the diff. If that's missing, well, there's your problem... Assuming it has an AWD driveline, my suspicion would be that the center diff that is supposed to ...


6

You'll find the following will all affect your speed and acceleration: wind speed - a head wind will slow you down more than you would think your clothing - this directly impacts drag bike configuration - you'll go slower with panniers on than with them off weight - a full tank will mean you accelerate more slowly temperature - cooler air can give you a ...


6

It is actually really difficult to top this up yourself - the easiest route is in through the transmission dipstick, so you'll need a long funnel. First, find the dipstick - it will be inwards and down below the fuel filter (your manual should show you where) - it will have a yellow circle at the end, for your finger to pull it out. Then see how full the ...


6

All wheel drive vehicles connect the front and rear axles via a transfer case or differential. While on a wheel lift tow one set is lifted off the ground and not spinning and the trailing wheels are spinning at road speed. This places a big load and resulting wear on the power transfer unit. Coasting allows all four wheel to spin at road speed but with no ...


6

It sounds like they're trying to take you for a ride to me. I can't see how driving style could cause the slave cylinder to fail - they're separated by a mechanical linkage. I would also dispute that anyone could destroy a clutch with 32k of normal driving - I'd expect it to last at least twice that long. However, a leaking cylinder might cause ...


6

I think it's more related to the angle of the driveshaft from the transmission to the differential. This way you could have more suspension travel without putting too much constraints on parts. In fact, to answer your question, it may be related to the geometry of the truck/driveshaft that manufacturer will select one type over another one. If the truck is ...


5

DURING cranking, in Neutral, the car races forward The transmission is not in neutral, no other explanation. Check the shifter linkage, it may be out of adjustment, or bent. Those are the most likely causes IMO based on the fact that you put a clutch in the vehicle and the linkage would have been disconnected and reconnected in that process. The ...


5

Being in Neutral or Drive should have negligible to no effect on the distance the vehicle travels when the accelerator is not pressed because the torque converter disengages the engine below predetermined RPM levels. However, if you somehow were to push just a little too hard and sent the transmission into Reverse instead of stopping in Neutral, you would ...


5

It's doubtful that any damage was done. The rev limiter should have prevented any damage from occurring to the engine and driving in a lower gear won't hurt the transmission.



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