automatic car

I drive a honda accord (automatic), and a friend of mine advised me that
when I am driving downhill, I should shift the gear to 3rd gear from D. If
I do it everyday, 5-6 times daily, will it lower the performance of the car
(gearbox) ? Or am I simply doing the right thing as anyone should be doing?

Philip

 

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.

 

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.

 

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...

<G>

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