automatic car

if it's a steep hill that would have you shifting to 3rd on a standard transmission, go ahead and do it. in fact, hondas downshift for you on hard braking. it doesn't have any detrimental effect on the transmission.

*Myself*, I would leave it in drive unless the hill is super steep, and you need the extra engine braking to help keep from burning up the brakes. On just everyday hills, I would leave it in drive. The tranny will know if it needs to downshift. You really don't have to do it yourself. Ditto for going uphill. It will downshift automatically if it needs to, to keep from lugging the engine. On most smaller to medium grades at highway speeds, I would prefer to stay in OD unless it starts lugging. Saves gas. If you drive down a hill in OD, and switch to 3rd gear, all you are doing is burning extra gas and adding a slight amount more engine wear due to higher rpms. Unless you *really* need the engine braking , I don't see the point of going to a lower gear. I'd rather stay in OD if above 35-40 mph. MK

I have never understood the recommendation to use engine/transmission braking instead of the regular brakes to slow a car down. I would much rather change brake pads than I would repair internal clutch packs in an automatic transmission. For that matter, I would rather do brake work than I would replace conventional clutches on manual transmission cars, especially for front wheel drive vehicles.

Unless there is a reason why the brakes are not up to the job, I use them to do all of my slowing down.

The only time I might manually down shift and automatic is when traveling on roads which constantly change from uphill to downhill and thus cause a lot of extra shifting of the transmission.

John

using the engine is "free" braking. using the brakes is not. once the pads get hot, efficiency decreases, and in extreme cases, fade to almost nothing. needless to say, you don't want that. [ask any truck driver that's used the emergency run-off ramps on grapevine in southern california - i drive through once or twice a month, and every time there's a truck either in, just towed off, or the evidence of a fresh brake failure on those ramps.]

engine braking does not consume clutch packs in the automatic any more than any other shifting. in fact, it's less wearing than a full power acceleration shift.

see above.

for a lightweight vehicle in ordinary use, you can get away with this just fine. for a heavy vehicle, or a vehicle in heavy use, it's a highly dangerous habit to be in. use engine braking and keep your brakes cool for when you may really need them.

you can get away with this

If engine braking is a good thing to do, then why do I see roadside message saying "Please avoid use of engine braking" at not-so-steep-ramp?

Thanks.

you can get away with this

because the jake brakes on trucks make too much noise for residential neighborhoods!!! why do /you/ think trucks have brakes like that???

Or "engine braking prohibited." I don't know why such ambiguous wording is used, and the "unmuffled engine braking prohibited" variation doesn't clear it up much. All of those refer to big rigs that use engine compression brakes, often called "jake brakes." I'm sure you've heard them on the highway in rural areas - a loud "brappppppppp" that can be heard a mile away. That's why they are restricted. Braking by selecting a lower gear is not only allowed, for heavily laden trucks it is mandatory. The CDL study guide here in Arizona - probably the same in all the lower 48 - warns a hill should be descended in the same gear that was used to ascend it.

Mike

Ever notice that brand new trucks don't make much noise when braking?

Seems, (at least around these heeyah pawts), that owner/operators have a nasty habit of removing the muffling material from their exhaust "to be kewel" or worse, to "increase power." These are mostly gravel and construction trucks.

I a big fan of engine braking and down shift on stops as a regular practice.

Of course on my vintage tin with automatics, engine braking is automatically applied when ever you take your foot off the gas....

JT

I do a lot of mountain driving. Downshifting saves your brakes. You dont want them to go out after hours of using them. A rule of thumb is, if you are using your brakes a lot, then you are driving incorrectly. (Applies to flat land driving too.) I can usually tell who the tourons are by excessive brake lights.

Every extra shift is extra wear.

Engine braking also puts load on the bearings and rings for no productive purpose. Heck, it even puts strain on the throttle butterfly bushings.

For ultra heavy trucks this is of course an entirely different discussion.

For passenger cars in normal use, not trailering and now packed to the gills, the extra shifting is to no benefit.

John

Recent Accords have "hill logic", or something like that, which has both uphill and downhill features, including some engine braking, as I understand it.

I agree with John, in any case you'd much rather use up some brake pads then ask your aluminum-block engine to rev hard and slow you down. If your car is less than five years old, I'd leave it in drive. For that matter, if your car is older than five years, I'd still leave it in drive!

J.

Looking at it from another standpoint (saving gas), I put my car in neutral down long hills and just use the brakes. Never had a problem.

that is about the worst thing you can do.

in order of darwin award qualification:

1. your brakes are much hotter than they need to be.
2. you don't have the engine engaged in case you need it.
3. you're burning more gas than coasting in gear.
4. in some states, coasting in neutral is illegal.

again, you are NOT saving gas in neutral - in fact, just the opposite. fuel injected systems do not inject gas if coasting *above* a given rpm, [say 1,500], so you coasting and allowing the revs to drop below that limit ensures the engine has to keep having fuel injected.

Heh... Maybe he rides the clutch to compensate...

JT

With disc brakes it isn't as big a problem, but I remember driving our family '67 Chevy with 4-wheel drums down a long descent somewhere near Bonny Doon, CA. I had the two-speed automatic in low gear (top speed about 55 mph) and within a few minutes I had both feet braced hard on the brake pedal continuously. I was lucky to find a flat spot where could I pull off. I tried to let the brakes cool, but after 15 minutes they still had no significant effect. I got rolling slowly and they cooled enough to keep my speed under 40 mph. It was pretty scary.

Mike

dont wear your transmission out over somebodies bad advice. it's not a stick shift it's an automatic. if you want a stickshift buy one. if you drive through a mountain area leave it in D3 some of the time. you will ruin your transmission driving it like that daily. make no mistake.

-jeff