knucklehead_11

Actually (different car, I know, but still) the automatic in my Honda doesn't downshift while braking. But, the again, the design of the automatics used in Hondas are different than others in that there is no planetary gearset. But yeah, no downshifting. When I apply the brakes to come to a stop the RPMs just go down and never jump up to signify a gear change, and if I need to push the gas pedal in some more it goes into the appropriate gear. Maybe it's a Honda thing...

Kahdir

I down shift & brake @ the same time... I guess I've been lucky with my Jeeps in the hills of PA

Paris MkVI

This is EXACTLY the technique. It's called "heel-and-toe" downshifting. Your right foot straddles the throttle and brake. You brake, and twist your leg at the hip to blip the throttle up. That way your brake pressure remains constant.

At the top of the throttle-up, you downshift. Your engine revs and gear selection match (if you've done it right) and you have a smooth downshift, ready for acceleration once again.

It takes a while to master the technique, but it makes you a much smoother driver. And you still get that rush of engine music when you blip the throttle!

spike

Yup, I'm with Paris MkVI. It all really depends how you drive stick. If you don't heel-toe, it's probably a waste to down shift.

I've driven stick since I could drive so a lot of the mechanisms of shifting are natural to me including heel-toeing. If it's not comfortable, then don't do it.

btw, you can actually shift without using the clutch at all by heel toeing (you must have really really good knowledge of speed vs rpm on your car to do this). If all trans parts are moving at the same speed, all the gears will easily slip together.

Rev matching is also the safe way to get from neutral to gear while at speed. While in neutral with clutch out, get the rpms up to gear speed, clutch back in, then shift into that gear. No harm to trans/clutch/whatever.

ONE NOTE: Heel-toeing works best if you put the trans in neutral before "blipping" the gas. This gets the clutch plate up to speed too so that the fly-wheel, clutch plate, and gears are all moving at the same speed. Absolutely zero slipping of the clutch while down shifting.

jarradasay

In most states it is illegal to coast in neutral for the very reasons stated in previous posts. Trying to fumble gears in an emergancy situation is a bad idea. One thing to avoid is downshifting too early. You can tell when you do this, although the accompanying exhaust burble is great. It is not good on the engine to downshift from 5th to 2nd. Shift from 5-4-3-2 and then into 1 when you stop. This guarantees you'll be in the correct gear if an emergancy comes. You should apply your brakes at the same time you are down shifting, God gave you two feet for a reason. This ensures following traffic will know you are slowing down.

But at the same time I have seen signs in many areas that state " no engine braking". I surmise that this is directed at semi's that break noise ordinances when downshifting.

Rash

This thread has finally made me stop second-guessing my decision to buy an automatic.

RKNMACH

Been downshifting since 1960 and never had a problem with clutches or synchros. As many have already posted, adding a few revs while shifting to a lower gear avoids any harsh wear on the clutch and drivetrain. The drivetrain is at more risk when you are in a WOT mode or powershifting. But of course none of us do that....

05GT-O.C.D.

OMG I can't believe some of the things in this thread. Down shift to your little heart's content and for God's sake, don't let an internet thread keep you from getting a manual transmission.

I've ALWAYS downshifted in my cars, trucks, and SUV's and have NEVER had a problem. That includes hundreds of thousands of miles while delivering pizza, towing lawn/landscape equipment, and a 3500lb boat. Sure it can cause some additional wear, but will not cause any failure unless you're a moron about it. Don't try downshifting into 2nd at 80mph, but if you're in 5th gear and drop into 4th you will not hurt a thing. I've only lost one transmission, and that was an automatic with 80k miles.

Question: Do automatic transmissions shift themselves into neautral when coasting? (I honestly would like to know)

Don't be a pansy, drive your car how you want and enjoy it. :drive:

SonicStanGirl

I belong to the "save the expensive parts" club and use mostly brakes for braking. I think downshifting while decellerating before turns is essential and sometimes the downshift + brakes is needed in situations to decrease stopping distance plus I do have fun with the exhaust sounds and downshift just for that sometimes...but I try to keep that to a minimum with this car.

I have had a manual tranny in all of my cars and even though with other cars I downshifted A LOT I personally have never burned out a clutch. I just don't want to hurt this particular car. Plus, my BF has a heavy clutch foot (as evidenced by trips in my old car that end with a stinky clutch) so by me not downshifting to brake I hope to influence his habits.

SonicStanGirl

LOL!!

AWmustang

The brakes in all levels of Mustang are capable of locking up all four wheels (though ABS prevents this in some models). In no way does down shifting add any extra slowing force above what the brakes are capable of. (Locking up the wheels is not the quickest way to a stop, but if you can lock them up, you have plenty of stopping power to get the quickest stop)

Now in the case of long downgrades, of course downshifting is neccessary.

I'm not saying don't downshift, just pointing out that it isn't needed to decrease stopping distance.

msd

No. Many actually upshift to provide engine braking (I assume they do this for smoothness, and to keep the car from engine braking too quickly). Once you apply gas again, it will downshift to appropriate gear. They will never shift to neutral; think of what would happen if you were going downhill.

http://auto.howstuffworks.com/automa...ansmission.htm

PS - I orginally thought they downshifted

SonicStanGirl

Ya, I shouldn't have said NEEDED....better word would have been OPTIONAL.

TexaStang

Why do you have to slip the clutch to downshift? I just roll my foot over while on the brakes, match revs, donwnshift, and be done with it. What happens if you are coasting in neutral to a light you need to make an emergency manuver? Just something to think about.

clintoris

I think the rev matching spoken of earlier and what you're talking about are 2 different things. The technique you're talkin' about is known as double clutching. That way your synchros are all lined up. Rev matching by tapping the throttle is only going to speed the flywheel up so that you don't lurch forward so hard.

Either way... I downshift. It's good for me. It makes me happy, and hasn't left me on the side of the road yet. I'm willing to bet it won't at any point in time, either.

wjones14

I agree with some of the posters who said they downshift to always be in the right gear for when they accelerate again. So that makes perfect sense when braking for a corner. Or maybe even a red light that might turn green before your car is stopped - good to be in the correct gear in that case.

But to me there is no real point to downshifting through the gears for a stop sign. That's just unnecessary wear on the drivetrain. I usually just brake until the rpms are down near 1000 or so, and then push in the clutch as it's coming to a stop for stop signs.

Little Black Pony

Which, is the recommended method.

But...

This brings up another touchy issue.

Holding the clutch pedal to the floor while waiting for the light to change.

Long ago I learned never to do this. Mostly cos the older '60s style clutch components weren't as well engineered as they are today. So inevitably they wore out quickly. Also, I used to own several cars that were 40+ years old and avoiding having to replace clutch components was a big deal.

Ok, so one of the things I learned was that keeping the clutch pedal to floor while waiting for a light to change wore out the throw out bearing real quick. Not only that but it put a lot of strain on the ol' clutch cable and associated bits. (modern cars don't really have that problem cos the clutch is operated hydraulically)

You see when the TOB is engaged against the pressure plate it sits there and spins with the RPM of the engine. The spinning bearing eventually heats up due to friction from the ball bearings inside rotating against the offset pressure of the bearing race within the bearing housing. So, if you leave it engaged for, lets say 3 minutes (the typical time a light stays red) then your TOB will begin to heat up and over time this will eventually break down the grease inside the bearing leading to failure of the ball bearings. Yeah, not a pretty sight. I've seen a lot of grenaded TOBs. Not pretty.

So, feasibly those three minutes that the TOB is sitting there spinning and heating up are three minutes worth of service life you just used up on that part. After a couple of years that adds up real quick. See where I'm going with this? The less the part is used the longer it will last.

BTW, the older clutches weren't all nice and soft like they are today. You really had to muscle them down. Depressing the clutch for that long either made you tired or gave you one leg bigger than the other. Haa haa

knucklehead_11

I wish they had a howstuffworks for the Hondamatic. My automatic doesn't have a plantary gearset. Meh... oh well. It shifts, that's all i really care to know right now lol.

official_style

its fun, if u know how to do it and match revs doesnt do anything to the clutch, i bought the car to enjoy, not baby. i have done this since i got the car. i got 22k on it. whats next dont do burnouts and donuts and chirp 2nd lol. its a MUSTANG. this is what they are for.

sscobra

I do believe in the "brakes are cheaper than other parts". I just have never seen a reason to downshift to slow down. One point I haven't seen brought up, is the stress on the engine. Mainly the thrust bearing for the crank. When downshifting to brake you reverse the pressure on the crank thrust bearing. This wears out both sides of the bearing. I know some say well I have downshifted to brake and none of my stuff has broke. That's fine that's just a compliment to the engineers that designed these cars to take people's abuse. I have rebuilt many engines. I have seen several cranks where the thrust bearing wore a grove into the crank(you would have never known this, until the crank failed or was taken out). It was only a matter of time until that crank failed. Also, if you ever want to rebuild your engine the crank would be scrap metal. That's just my opinion. I try to only downshift to go faster, lol.