Exploring the Power of Downshifting: My Auto's Transmission Gear Selector

[Cyrus]

I drive an auto. On the transmission gear selector, there is

P
R
N
D4
D3
2
1


My friend showed me that you can downshift from D4 to D3, and you can feel the car slow down from the downshift. So now I find myself playing around with it all the time. Do you think this is bad for the car? I do.

Oh well, it's not like I care, this transmission is shot again anyways . I'm on my 3rd, tranmission already with only ~110k miles. Honda is obliged to replace my transmission for free, so in any event, I'm not going to stop what I am doing.

I think my tires outlast my transmission(s)!

 

[Astronuc]

Automatic transmissions were not really designed with downshifting during operation. If one downshifts frequently, I would imagine that it will shorten the life of the transmission by stressing seals and components.

I sometimes downshift my auto, but I shouldn't.

I miss manual transmission.

 

[brewnog]

Three Honda transmissions in 110k miles? You're definitely doing something wrong!

What's wrong with using the brakes for slowing down?

 

[Cyrus]

I think your civic has more HP than my accord astro,


The transmission is junk brewnog. That's why Honda keeps giving me new ones for free!

 

[wolram]

Ha, Ha, i can just imagine it spewing gears and trany oil down the road.
but seriously i am sure you could buy some thing better for 500$ or so.

 

[BobG]

Three Honda transmissions in 110k miles? You're definitely doing something wrong!

What's wrong with using the brakes for slowing down?

With an automatic (or manual, for that matter) transmission, you shouldn't be changing the gears. You're extending the life of $20-$40 brake pads by shortening the life of an $800-$1600 transmission. The other settings are for unusual circumstances.

For example, on a slick road, you really don't want to be using the brakes a lot (although this isn't as big a problem with anti-lock brakes). You're better off going with a slightly lower gear to keep your speed down without having to use the brakes. It's not great for your gas mileage, since it means you're using a higher rpm, but the car slows as soon as you lift your foot off the pedal instead having to use the brakes.

Going down a mountain would be another good time to use a lower gear. If you're using your brakes too much in a short amount of time, they'll heat up and your brake fluid will heat up. Your brakes will fail if they get hot enough. Every couple of years or so, we have tourists drive off the side of Pikes Peak when they don't believe this (in spite of the mandatory brake check point at Glenn Cove - some don't want to wait their turn to have their brake temperature checked and find a way to sneak by).

 

[Cyrus]

With a manual transmission, you shouldn't be changing the gears. You're extending the life of $20-$40 brake pads by shortening the life of an $800-$1600 transmission. The other settings are for unusual circumstances.

For example, on a slick road, you really don't want to be using the brakes a lot (although this isn't as big a problem with anti-lock brakes). You're better off going with a slightly lower gear to keep your speed down without having to use the brakes. It's not great for your gas mileage, since it means you're using a higher rpm, but the car slows as soon as you lift your foot off the pedal instead having to use the brakes.

Going down a mountain would be another good time to use a lower gear. If you're using your brakes too much in a short amount of time, they'll heat up and your brake fluid will heat up. Your brakes will fail if they get hot enough. Every couple of years or so, we have tourists drive off the side of Pikes Peak when they don't believe this (in spite of the mandatory brake check point at Glenn Cove - some don't want to wait their turn to have their brake temperature checked and find a way to sneak by).

When they fly off the cliff, does their car explode like in all the movies?

 

[Danger]

My El Camino has a Turbo-350 automatic with manual valve body, so I can downshift to first at 100 kph if I wanted to ( ). I do downshift (gently) to decelerate, because the rotating mass of those 33" tires has the brakes squealing within 4 blocks of home if I don't. I've had no tranny problems in several years of driving it that way. It's also, by the way, not great for the rod and crank bearings, but they're still okay.

 

[BobG]

When they fly off the cliff, does their car explode like in all the movies?

More pathetic than that. Whenever it happens, you get the eyewitness reports of people going up the mountain that saw them coming down. Once the brakes go, instead of putting the car into first or even park or reverse (so long tranny), they're more likely to think turning the ignition off might help. So long steering.

It would almost be funny if there didn't seem to always be an entire family along for the ride.

 

[brewnog]

It's not great for your gas mileage, since it means you're using a higher rpm, but the car slows as soon as you lift your foot off the pedal instead having to use the brakes.

Actually, in a fuel-injected car, it's better for your MPG figure. On the overrun, the ECU will stop injecting fuel. If you choose to coast (thinking it will save petrol) then you end up worse off by having to still use fuel to keep the engine turning over!

 

[Schrodinger's Dog]

That's really interesting, I've only driven a few times so can't help, but am a big F1 fan and they use the breaks almost never only for emergencies, mind you they do have the luxury of a 1 warm up 1 engine 1 race, ie it's designed to last exactly 300 miles or so, downshifting four gears slows you down more smoothly and allows you to ride the corners better, streets(bad word unless it's Monaco) better than just breaking too

I've always had an interest in cars, it's odd because I've never owned one, luxury of living in a small country but I watch all the car programs with a strange fascination, it's like a fish watching people walk and run from the tank

You guys should try down shifting on a bicycle, now that is great fun legs go windmill and you end up in the back of the car you were trying to slow for: oops, same principle but way different results

 

[brewnog]

That's really interesting, I've only driven a few times so can't help, but am a big F1 fan and they use the breaks almost never only for emergencies, mind you they do have the luxury of a 1 warm up 1 engine 1 race, ie it's designed to last exactly 300 miles or so, downshifting four gears slows you down more smoothly and allows you to ride the corners better, streets(bad word unless it's Monaco) better than just breaking too

No, they use the brakes extremely heavily too. Seen them glow?

You guys should try down shifting on a bicycle, now that is great fun legs go windmill and you end up in the back of the car you were trying to slow for: oops, same principle but way different results

Not the same principle at all; the freewheel mechanism removes any 'engine' braking effect from a bicycle.

 

[Astronuc]

I think your civic has more HP than my accord astro, The transmission is junk brewnog. That's why Honda keeps giving me new ones for free!

Actually, at the moment I'm driving a '96 Odyssey, which was the car my wife drove. We bought her an newer Odyssey, and I traded in what was left of my 4 dr Civic EX sedan, which had about ~190,000 mi IIRC. It had rusted through on both rear wheel wells, needed overhalls of the transmission and engine, and I needed to patch the hole in the passenger side floor - courtesy of some idiots front end debris which I hit at about 60 mph. I didn't see it because there was a car in front of me that passed over it first and it was early in the morning. The damage came when I pulled off the road and hit the grooved shoulder which wrenched the metal bracket around and gouged a 12" gash in the floor. I was on my way to the airport for a business trip, so I couldn't stop and deal with it - I just removed the bracket from under the car and drove to the airport. I was in bad mood that trip.

 

[Cyrus]

Oh man, that Odyssey is fast. It always kills my accord !

One night I was driving home this semester at around 4 am, and on a major road some idiot kids thought it would be a funny idea to put all the trash cans in the middle of the road. This road is big, 3 lanes each side, but no street lamps. So I'm going 60mph and then all of a sudden I see this black trash can coming up. SWERVE left, ANOTHER trash can, SWERRRVE right. I was weaving like a drunk. There was one guy behind me by maybe 100 feet or so. He must have thought to himself, WTF is that guy doing, is he drunk?? ...unitl he came up to that same obstacle course and started weaving. He must have said to himself, oooooooooooooooooh now I get it.

 

[Astronuc]

The next car will probably be a Honda Civic, manual 5-speed or hybrid, or one of the other Hybrids. I prefer high-mileage. I don't worry too much about acceleration. Around town, I am usually not in a hurry to get somewhere. On the highway, I just keep it constant and fast.

Speaking of buying cars, I love to go into the auto dealers with a calculator or laptop with programs for interest rates and payments. It initimidates the seller when one can sit there and independently check interest rates and plans.

I had one guy try to sell me a more expensive finance plan, which had a lower interest rate, but one paid more upfront. He was a bit distressed when I whipped out the numbers in front of him - he had to leave momentarily.

 

[Astronuc]

I ran over a deer at night - he was already laid out on the road. It was on a dark country road and I came upon it so fast, I didn't have time to swerve. It was like driving over a speed bump too fast, and the antlers rattled the undercarriage as I went over the head. This was a years ago. I was relatively new to the area - I had just moved there - and I had never encountered large objects in the middle of the road before.

 

[moose]

Speaking of buying cars, I love to go into the auto dealers with a calculator or laptop with programs for interest rates and payments. It initimidates the seller when one can sit there and independently check interest rates and plans.

Lol, my dad uses the program he made for his pda. I know exactly what you mean