Downshift or just brake to slow down with automatic transmission?
WÇY
downshift besides braking to slow down the car. However, I am now in
my second automatic and continue to use the same technique. My former
car was an Audi 100 with a four-speed auto transmission. I used it in
this manner for five years (160.000 Km) and it seemed to be in perfect
condition when sold. I now bought a five-speed sealed-transmission
automatic Mercedes E240 and drive it the same way. The car also shifts
down with no problem. (Neither car would accept downshift if that
would put the engine above accepted RPM).
However, I have began to wonder if this is approved technique in
autos. Perhaps in these cars the transmission is not intended for
downshift and I am placing an undue stress on it? Undoubtedly,
changing brake pads is much less costly than having to change the
transmission.
I would appreciate expert and knowledgeable advice on this matter (not
just opinions).
Thanks very much for your input.
The.Central.Scru...@invalid.pobox.com
>I have owned manual transmission cars all my life and am used to
>downshift besides braking to slow down the car. However, I am now in
>my second automatic and continue to use the same technique. My former
>car was an Audi 100 with a four-speed auto transmission. I used it in
>this manner for five years (160.000 Km) and it seemed to be in perfect
>condition when sold. I now bought a five-speed sealed-transmission
>automatic Mercedes E240 and drive it the same way. The car also shifts
>down with no problem. (Neither car would accept downshift if that
>would put the engine above accepted RPM).
>
>However, I have began to wonder if this is approved technique in
>autos. Perhaps in these cars the transmission is not intended for
>downshift and I am placing an undue stress on it? Undoubtedly,
>changing brake pads is much less costly than having to change the
>transmission.
Just use the brakes. Brakes have come a long way since the 40's and fade
isn't so much of a problem.
Brakes are a hell of a lot cheaper than the wear and tear on the
engine/transmission from engine braking.
Nathan Nagel
yup.
Only time I would use engine braking in an auto is descending a long
grade, any other time just use the brakes. Brakes you can replace
yourself and pads are cheap, auto trans internals are much more a PITA
to fix.
nate
py...@texas.next
An auto trans is not direct connected to the engine during
slow down. Power goes through the torque convertor which at best
is <90% efficient. The 10%+ loss is turned into heat.
Your trans is being fried.
shiden
"WÇY" wrote
So how are you going to figure out whether you are getting expert
and knowledgeable advise unless you ask what people's qualifications
are? Probably best to just take everything with a grain of salt and
use common sense.
I wouldn't bother manually downshifting in an automatic. There is
really no point unless (as another poster mentioned) you going down
a long grade and want to keep the speed under control without
riding the brakes. But on the other hand, I wouldn't get all worried
that you are wrecking your trans because you happen to be used
to shifting down manually. It just isn't necessary and that's all that
is really important.
Frankly, it's not particularly necessary with a standard trans either.
I often will simply put the trans in neutral as I'm slowing down and
pick the appropriate speed when ready to accelerate. Or I might
just row thru all the gears on the way down. Whatever turns your
crank..
Ian
Robert Hancock
downshifting is necessary to prevent overheating the brakes. It puts a bit
of extra wear on the trans. from the extra shifting, and also probably
creates some more heat in the torque converter. Like others have said, brake
pads are much easier and cheaper to change than repairing a transmission..
--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from hanc...@nospamhome.com
Home Page: http://www.roberthancock.com/
"WÇY" <WÇY...@czerny.labs> wrote in message
news:sh9dhto1aeqk0ku52...@4ax.com...
Michael Groszek
Bret Taylor
>I often will simply put the trans in neutral as I'm slowing down and
>pick the appropriate speed when ready to accelerate.
I read in a racing book that downshifting to slow down, in a manual trans,
is an incorrect driving technique. The reason to downshift is just as you
describe, to pick an appropriate gear when ready to accelerate.
Don Stauffer
"brake linings are cheaper than clutch linings." :-)
--
Don Stauffer in Minnesota
stau...@usfamily.net
webpage- http://www.usfamily.net/web/stauffer
Rick D.
at a stop, I will downshift to 2nd or 1st b4 decending a steep grade,
especially where I need to maintain a lot of control, my oldest car
(Maverick) is non-power drums all round, that's where I picked up the habit
(major brake fade on steep grades if you're not careful). Other than grades
I don't bother to downshift and don't see the use or the good of it, like
other posters have said, just unnecessary wear.
My '94 Sable owners manual says it's okay for occasional use like grades,
etc, just to not exceed x number of RPMs in low gear.
In a slightly related subject, that same car's manual mentions the slight
engine braking benefit of driving it in D for city use as opposed to OD (has
drive and overdrive on the selector)- and as it turns out I do prefer city
driving in D.
Rich
--
---------
RickyRaccoon's Tree
http://rickyraccoon.50megs.com/
The Rusty Maverick/Flaky Mopar
http://rustymaverick.50megs.com/
"WÇY" <WÇY...@czerny.labs> wrote in message
news:sh9dhto1aeqk0ku52...@4ax.com...
Ken Hilson
miles I had to replace a clutch plate and piston. $1,200 CDN. I don't
downshift any more.
Alex Rodriguez
says...
Unless you are unhappy with the braking performance of your car, why do
this? You are putting uncessary wear and tear on your engine and drivetrain.
Brakes are cheap and easy to replace.
--
-----------------
Alex __O
_-\<,_
(_)/ (_)
MC Fabulous Jaguar
MC
MC Fabulous Jaguar
downshifting so there won't be any speed difference betwixt the flywheel and the
clutch disc. If you just jam it in a lower gear and release the clutch you will
whip the clutch in fine style. 8-)
MC
Michael Groszek
cars don't even bother with having to turn overdrive on. It is the default.
Overdrive is the 4th gear so obviously engine braking is better when you turn it
off and it goes into 3rd. Put your car into 2 and it will be even better.
Rick D.
(epsecially the way I drive), especially if you're only reaching speeds
where the OD kicks in for short periods. I suppose there might be a slight
amount of extra wear by having it slip in and out of OD all the time, that
might be a reason to leave it off besides my perception of drivability (and
the Sable manual mentions the wear issue too) but apparently not enough to
worry about- my '88 LeBaron does not have a seperate OD position, an aunt's
'88 Celebrity does, my '94 Sable does, my mom's '99 Mystique doesn't... it's
all in the whim of the maker I suppose. When there's a choice, I take
advantage of it. Makes a bit of difference with that Sable, when in OD that
thing wants to coast longer and it's more controllable and enjoyable to
drive for me, in city traffic, if I just leave it off. Not a whole heck of
a lot of difference but enough for me to notice it. Must be the engine/car
combo (fair sized car w/3.8L V6) because the LeBaron automatic OD has never
particularly bothered me in traffic. Same with the Mystique, doesn't seem
to get in the way. But the Sable is slightly more nimble w/o it.
Rich
--
---------
RickyRaccoon's Tree
http://rickyraccoon.50megs.com/
The Rusty Maverick/Flaky Mopar
http://rustymaverick.50megs.com/
"Michael Groszek" <mi...@dingoblue.net.au> wrote in message
news:3B1874C5...@dingoblue.net.au...
S Crook
"Nathan Nagel" <njn...@worldnet.att.net> wrote in message
news:3B16A9F9...@worldnet.att.net...
> The.Central.Scru...@invalid.pobox.com wrote:
> >
> > On Thu, 31 May 2001 22:15:26 +0200, WÇY <WÇY...@czerny.labs> wrote:
> > >I have owned manual transmission cars all my life and am used to
> > >downshift besides braking to slow down the car. However, I am now in
> > >my second automatic and continue to use the same technique. My former
> > Just use the brakes. Brakes have come a long way since the 40's and
fade
> > isn't so much of a problem.
> >
> > Brakes are a hell of a lot cheaper than the wear and tear on the
> > engine/transmission from engine braking.
>
> yup.
>
> Only time I would use engine braking in an auto is descending a long
> grade, any other time just use the brakes. Brakes you can replace
> yourself and pads are cheap, auto trans internals are much more a PITA
> to fix.
>
> nate
Agreed!
For steep down hills downshift BEFORE the downgrade to prevent reaching
excess speed (as opposed to reducing speed once it becomes excessive for the
conditions.
Even w/ manual x-mission take advantage of the brakes too and save clutch
wear, though downshifting can be used to achieve moderate speed reduction
and/or to augment brakes.
S Crook
on downshifts to achieve braking effects.
"Michael Groszek" <mi...@dingoblue.net.au> wrote in message
news:3B172C38...@dingoblue.net.au...
Milspec4
just opinions). Thanks very much for your input. <<
experience that may help, but not advice. No two marques are the same regarding
ATs and brakes and people like to drive differently. Drivers may have to adapt
to a particular 'local' pattern to stay safe, although some patterns are
commonly 'National' in different countries.
Most US drivers wait too long to apply brakes and then have to apply them too
hard. According to GM this may lead to disc 'fissuring', xs pad wear and,
eventually, disc failure. A driver who uses brakes 'properly' is in danger of
being overly tailgated & rear-ended or having others spurt past, requiring
several readjustments for safe spacing before a full stop.
You've haven't heard the story of the little old lady from north of Hartford?
She left her home to drive 3 MILES SOUTH to Hartford. She drove more slowly
than normal traffic. They kept cutting in front her and forcing her to slow
down to keep from hitting them. 30 minutes later she was 6 miles NORTH of
Hartford and three miles North of her home. So she did a 180 and started
driving the other way. They say she had been a drop-out from some Ivy League
school.
My Audi, while fully stopped, was rear-ended lighty, 3 times at 3 consecutive
stop signs in NYState where 'rolling stops' may be the norm. At that time they
made 'real' bumpers, so no damage. So many drivers have come down Pike's Peak,
with brakes only, that the Rangers check their wheel temps at the bottom and
ask them to park, until they cool, before they will let them leave the Park.
While driving a 7+ ton GVWR Chevy P-32 truck chassis, considerably, thru the
various Rocky Mountain passes [with often a temporary 16k GVW], it was
necessary to use both AT and 'metallic' 4 wheel disc pads, intermittently of
course, to maintain proper speeds for good control on unfamiliar roads with
many curves and 10 - 17% grades. In that rig, in 2nd or 1st gear, if the never
exceed speed was exceeded, the AT would kick out to neutral. Ist was 35mph &
2d, 65. If above these speeds in a higher gear, they would not engage. There
was a Tran Oil Temp gauge with the sensor at the tran outlet [factory placement
is not in the pan] to the Tran Oil Coolers. Topping a long, steep rise, temps
might be in the high 290s [never exceed is 300F]. Initial downshift speeds
would vary with the % down grade and but one thing always happened. No matter
the % of the down slope, the TOT gauge always started down immediately and out
of the low red to the green, level-road temp of 185F; or lower if the slope
were very long. From LEVEL onto a DOWN grade, requiring down shift or not, the
TOT always went DOWN. This suggests the TC does more work [more heat] hauling
weight level than it does when holding it back.
Thru habit [the way I was taught], I apply brakes lightly [sometimes rapidly,
intermittently] to warn a tailgator and down shift; keeping safe, stopping
spacing with the preceeding vehicle and an eye on the rear view mirror.
[I had a high-speed flasher on the brake circuit at one time. That got their
attention, but the cops in some states objected.] Usually, some following car
will spurt ahead of me then jam the brakes on. They have no concept of greater
momentum requiring more distance. I've used this slowing routine with a past
Audi 100, Saab, Continental, Datsun, Thunderbird [all ATs] and an Escort 5
speed manual. Not yet with the Subaru Legacy as I haven't finished reading the
shop manual and am unfamiliar with the marque's general history. [The Saab
front pads needed replacement each 2000 miles, but the AT was American made at
the time.] So far, no problem with any trans or engine.
Tailgators Beware: I Stop for Redlights and Stop Signs. In California, rather
than rear-end you, they tend to go to the right shoulder and overlap you. In
Jersey -- well you see them on TV at 'lead & bleed' time.
Opinion: Do what makes you feel the most comfortable and gives you the best
control and safety in the conditions where you have to drive. [These days, to
be PC, breaking an old habit sorta requires a support group, a consultation
with a female psychologist and, perhaps, a personal discussion, on TV of
course, with an uncertified educator. You'll do OK! But, Good Luck anyway.
FINIS.
Mike Graham
>will spurt ahead of me then jam the brakes on. They have no concept of greater
>momentum requiring more distance.
I worked with a guy that used to drive a tanker rig. He specialized in
hauling food-grade acids, which meant the tank was 'open' - no baffles. He
needed about 100 yards to slow down before a stop, otherwise the load would
slosh back and forth and push him through the intersection, a few feet at a
time. There's a lot of 'push' in 60 tons of liquid with lots of room to
roam around in. Anybody trying to squirt in in front of him was liable to
end up shoved into the intersection and get t-boned. That's life, eh? 8-)
--
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Mike Graham | Steel-fitter and CWB-certified weldor
mike at metalmangler dot com | Raiser of horses
<http://www.metalmangler.com> | Tester of limits (esp. patience)
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Ken Hilson
clutch plate refererred to is an internal part of the automatic trans.
Richard Schumacher
a stop (as opposed to using engine braking by downshifting one gear
at a time) would do no harm to the transmission? Maybe even a little
good because that will remove the braking load from it.
It's certainly easier to bring my Jeep to a stop when it's in neutral.
Terry Henne
pads rather than the $7,000 trans to slow the car down. It's foolish to
punish a trans when it's not necessary or even needed.
Terry
Dr. Bob
all know how to downshift so as to not wear the clutch or synchronizer
rings.
Bob
----------------------------------------
In article <9f8e95$e1u$1...@freenet9.carleton.ca>, da...@FreeNet.Carleton.CA
(Ken Hilson) wrote:
>I have a 99 cavalier and was dowshifting to save on brakes. At 42,000
>miles I had to replace a clutch plate and piston. $1,200 CDN. I don't
>downshift any more.
>
> "Rick D." (bakedbe...@yahoo.com) writes:
>> I downshift mine on steep grades, that is to say, when already going slow or
>> at a stop, I will downshift to 2nd or 1st b4 decending a steep grade,
>> especially where I need to maintain a lot of control, my oldest car
>> (Maverick) is non-power drums all round, that's where I picked up the habit
>> (major brake fade on steep grades if you're not careful). Other than grades
>> I don't bother to downshift and don't see the use or the good of it, like
>> other posters have said, just unnecessary wear.
>>
>> My '94 Sable owners manual says it's okay for occasional use like grades,
>> etc, just to not exceed x number of RPMs in low gear.
>>
>> In a slightly related subject, that same car's manual mentions the slight
>> engine braking benefit of driving it in D for city use as opposed to OD (has
>> drive and overdrive on the selector)- and as it turns out I do prefer city
>> driving in D.
>>
>> Rich
>> [...]