Best way to slow down on big hills!

malibu
chevrolet

#1

Hello Car Talk!



I would like to get your opinion on the way my fiance likes to slow down.

We live in canyon country in northern Arizona, and instead of braking on many downhill sections of road she chooses to shift her 2002 Chev. Malibu Auto into a lower gear, using engine braking to slow the vehicle. I know semi’s use this practice to slow, but are our small car engines designed to do this, and is this a good practice to use or not?



Thanks


#2

Yes, she is doing it the correct way. There is no wear or harm added to the transmission, and the risk of overheating the brakes is avoided.
If you check the owner’s manual, I’ll bet that it advises one to do this.


#3

Your girl is a smart girl, and you would do well to listen to everything she tells you and always reply to everything she ever says to you no matter how much it might seem like exactly the wrong thing, this these two magic words. “Yes Dear”. Believe me, you will never regrett it as long as you stay with her.


#4

Yes.


#5

I’d say you have a good role model to follow in your fiance’s driving habit. The only downside would be if the motor rpms were in excess of 4,000 and that isn’t likely. Downshifting one or even 2 gears (assuming 5 speed auto) will keep the brakes from heating up and help you stop quickly if needed, say a deer jumps in the road or you come up on a rock slide.


#6

Yes, she’s doing the right thing. If you read the owner’s manual for just about any car it will recommend this practice for conditions such as you describe.

It doesn’t hurt the engine and it doesn’t use extra fuel. What it does is save wear and tear on the brakes.


#7

After many years of transmission repair. Downshifting is an O.K.practice on standard transmission but, over the years, we’ve found that people downshifting automatic transmission excessively had sooner transmission failures. This is due to the fact that an automatic transmission is design to push (powertrain compressed) no pull. This causes an accordian effect inside the powertain and is extremely hard on thrust washers. I’d recommend going to a brake pad that will handle the excessive braking. i.e. Performance Frictions Carbon Metallic Pads.


#8

That may have been true once, but it no longer is. They are all designed to “pull” now too. This is because all engines now shutdown all fuel flow (to increase gas mileage) when your foot is off the gas and the car is moving faster than xx MPH. While the gas is off, the transmission turns the engine to keep it ready to start back and to keep all the accessories going.


#9

Long ago when there were not so many automatic transmissions on the road, you could tell who had one because they would use the brakes so much on down hills.
You asked for the best way to slow down, but if you want the fastest way, just start an argument about the use of engine braking with her and you will find yourself standing by the side of the road, 'cause she is right. by the way, if you know you are about to start down a long grade, if you shift an automatic into drive 2 before you start down, it will not get so stressed by the engine braking as if you wait until you are already running too fast for comfort on those hair pin turns.


#10

Yea she is right. It is not a bad deal as any modern car should have enough brakes to handle any normal down hill roads. However Using the brakes will use more fuel and wear the brakes faster.


#11

Like all, the ultimate authority is the owner’s manual and if it’s anything like ALL the automatics I’ve had…It’s meant to be down shifted. Why in heck would they give you the option if they didn’t intent you use it ?
I know of at least one automatic (2010 4Runner), and I’m sure there are others, that according to a review, downshifts automatically when you let your foot off the gas. It even gets better mileage, so it couldn’t be hurting too much. With other trac/ stability control sensors, I’m sure it knows a lot more than we give it credit for.

Toyota is so far ahead of the times, they’ve been test marketing some vehicles that after starting, you put both feet on the brake pedal only, let up to go forward, push down to stop. Some people have not been properly educated in this technique and think it’s a malfunction…it isn’t…they’re just way ahead of the game.:slight_smile:


#12

You must be speaking of Blacks Canyon on 17. This is a stretch of road (either headed North or South) that I would practice the autotrans downshift.

About Blacks Canyon, I drove a 22" (whatever the Yellow rental trucks are) up this canyon and struggled to maintain 22mph. Once I got to Montana and unloaded the truck it was quite “peppy” around town.


#13

I am a flatlander but last November I was out in the Hills between San Fran and Seattle. The Chrysler 300 automatically down shifted while using cruise control to maintain speed. Caution about using Cruise control on wet roads.
Good Idea to see if your cruise behaves this way? (comments?)


#14

That seems pretty normal…maintaining speed on hills demand it occasionally.