Sup guys.....

Is it bad for an auto tranny if I downshift to engine brake?

There is this one particular road on SI that is extremely steep with a traffic light at the end of it. Whenever I go down this hill I will
drop to 2nd Gear (to engine brake) so that I can approach the traffic light(which is always red) at a slower pace.

I don't think this would be bad for the car but I'm wondering
what the general consensus is...

thanks

 

Thats why you have the ability to put the car into 2nd gear manually. I usually turn off my overdrive when I'm going down a relatively long and steep hill. That keeps the car in 3rd gear. Just make sure your revs aren't so high. 2nd might be kind of low, but isn't doing any harm thats for sure.

 

Actually it's bad for both transmission and engine simply because it unecessarily increases wear and tear on these very, very, very expensive parts. I think the use of engine braking is another carryover from the olden days when brakes- well- sucked and engine braking was critical to safety, but that's not the case any more.

You should downshift to use engine braking, auto or manual, only when descending long, steep, hills (like a mountain) carrying a heavy load where brake fade could set in. And, actually, I've read several experts claim even that is unecessary with modern disk brakes.

In the situation you describe I usually shift my auto into neutral as soon I see I'll end up sitting at the red light. I'd much rather replace the brakes sooner, several times, than chance an engine or transmission, even once, later on.

BuddyWh

 

yea that's a good point, but was under the impression that shifting into neutral while moving wasn't very good for the transmition in an automatic. my friends civic had to get a new trany cuz he liked to pretend he had a manual and shift into neutral everytime he wasn't accelerating.
but as far as engine breaking, i do it someimtes too, but i don't think its necessary.

Chung-Hsien

 

I thought it was a good idea once very long ago. Your manual might say something about it..and so will any other 'diving book'. But if you are replacing convential braking or supplementing braking for the most part with engine breaking it is not good. Ask any auto mechanic what is cheaper to replace- brakes or a transmission. I think that the Max has excellent brakes.

In any event, if you choose to, take note of your speed before just picking any gear to downshift into.

 

You think that the max has excellent brakes? Oh boy.... Here we go again

 

makes you wonder just how ****ty the brakes are in hell where he was exiled from!!!

 

 

Obviously you've never driven a 1963 Plymouth Valiant.... or any other car with drum front brakes. Try one sometime, you'll find out what ****ty brakes are really like.

A Max's brakes are very good, not great but no where near the level of ****ty.

Buddyw

 

Let's see....hmmmm, comparing cars that are almost 40 years worth of technology different....great case made there!!

Warping rotors left and right does not indicate a very good braking system. By the mere fact Nissan has a TSB on it shows even they realize it is a problem. Had the Max brakes been good, Nissan would not have had to do this and also would have considered any other warping driver abuse or other.

I don't know, how are your Max brakes going to be compared to say a 2042 model?

 

I Think that's the whole point of this argument.
Since technology has improved in braking, there is little to any use for engine braking. The 1950's cars had bad brakes so they had to help their brakes out with engine braking. Since our brakes are a lot better are disc and not drum, they are a lot better. Therefore, we really don't need to engine brake.

 

so you people are saying... downshifting and engine breaking even for MANUALS... is bad?

 

I can attest to that - although with a much newer car. Try any 95-99 Chevy Lumina's brakes and then come back and try a 5th gen Max's brakes and tell me which ones are ****ty and which ones are freaking outstanding (in comparison).

John

 

Bad? No. But smart? Also no. Think of it this way... which would you rather replace, a transmission or the brake pads? Manual or auto doesn't matter.

 

true... o well.. i always thought it was ok for manuals since there tranny's hold up better than autos. time to change my ways

 

Please post proof that engine braking is bad for slowing your car down. People always say this and I have yet to see anywhere that this is bad for the transmission. I've driven just about everything up to 30,000 pounds and over. I used engine braking when I needed to and never any problems.

 

I thought it was alright too!! What if you want to hit a corner at 50mph?!?!...back to downshifting!

 

How about you prove it's not? I've driven larger trucks, too, and the reason they use engine brakes is because the air brakes have a tendency to give out if you stay on them on a slope.

Stopping a car takes force. As drivers, we get to choose where that force is exherted... on the tranny or the brakes. Wherever you choose to exhert it, it will cause wear on that component. You not having any problems doesn't mean it didn't cause unnecessary wear and tear on the tranny and engine. I'd rather replace some brake pads than a transmission.

 

There isn't 40 years of technology difference between that '63 Valiant's brakes and a Maxima's. Disk brakes were well know then and the Valiant's drums are exactly like any other drums on many new cars today, albeit in the rear only. It's just that manufacturers now are much more concerned about safety and stopping ability with lots of fade margin so they build in better brakes.

Yeah, my left and my right front rotor warped too. Now I torque the wheel lugs correctly and don't brake hard from 130 like a fool. My brakes are very good... short, straight, sure stops, no judder, no fade, no off-on braking as one then another wheel locks up. No complaints.

In 2042 I expect a car in the Maxima's class to have brakes about like that on a motorcycle. If there's a car in Maxima's class at all it had best weigh about as much as a motorcycle or there won't be oil in the world to operate it. But the technology itself won't be very different at all.

BuddyWh

 

Uh, wrong!! Materials, electronics, design have all changed drastically. With your mentality, it is like saying a biplane from 1917 and a jet from 1957 aren't all that different since in the biplane's day they knew about flying.

 

How can you prove common sense?

If you work the engine harder by making it abosrb the energy of the cars mass*velocity it has to be bad for it as compared to NOT making it do that. Sure it can take it, but why when there are cheap brakes that do it much better?

If you want, justify it honestly: just say you love driving that way as it extracts maximum driving pleasure from the car. That's cool, cause that's why we accelerate hard too... or even turn the d**n thing on in the first place. And no one can argue running an engine isn't bad for it, but that just ain't fun now, is it!

BuddyWh

 

Don know for sure but:

For the engine braking I think it has something to do with compression rising since your're pretty much truning the pistons with a crank. I guess as long as you keep the RPMs in a low enough range it should be fine... otherwise it's like sticking it in the wrong gear - hear it go boom

Now engine braking with an auto is bad unless you have HD transmission cooler because basically TC is going to generate ton of heat working against lots of resistance on the output.

 

Surprise! there are no electronics in your brakes... and ABS don't count here. ABS usually decreases ultimate braking performance... I would disable it if I could and my wife never drove the car.

Second: design hasn't altered much, in fact in the case of mass-market disks and calipers it is vastly simplified for economy today compromising more than improving on '63 designs.

Third: materials, yeah we can't use asbestos linings today so we have to use exotic materials now, big deal. Metal alloys haven't changed much to affect performance. Seals? yeah... silicone and nitrile rubbers are nice 'cause they last much longer in service. But that doesn't improve performance.

Fourth (you left this out) manufacturing processes: this has improved. A lot. But these, along with design simplifications, are implemented mainly for mfg. economy and has allowed manufacturers to put disk brakes on cars today where they would only have put them on luxury or high performance cars in '63. That and growing liability concerns.

Look at a '63 car's drum brakes sometime... if you have grease under you fingernails you will recognize how surprisingly similar things are to today's drums. No... identical... not one thing is changed. Not one. It's like a time capsule.

Your analogy falls completely apart: friction braking is very simple physics in action, airfoil performance and airplanes are vastly more complex.

The better analogy would be to an anvil: how much has the anvil improved since 1802? 200 years? Not much.

BuddyWh

 

I'm with deezo on this.

You push an engine a helluva lot harder accelerating it than you do during engine braking. And it won't cause any excess wear because guess what, the engine is going to be turning over anyways. Oil is still flowing and friction is at a minimum and all you're doing is using the engine's compression to slow yourself down instead of using it to accelerate you. What's the big deal?

The last car in my sig, the 90 Toyota Camry 5spd had 207,000 miles on it when we sold it, and it was still running great. My dad used engine braking all the time in it for 180,000 miles, and then I ran it for the last 27,000 doing the same exact thing, and you know what? That engine was still as strong at 207,000 miles as it was the day it left the showroom, and would still get over 30 mpg on the highway at over 80 mph. At 207,000 miles! The only thing wrong with it at that point were hardened valve seals which resulted in a little blue oil smoke at startup and that's it. Oh yeah, we hardly EVER had to do any brake work in 207,000 miles either. We always got EXCELLENT brake wear. Imagine that! We must have saved a good chunk of change on brake work just from using engine braking, all with no bad side effects to the engine and drivetrain.

I manually shifted (intelligently) and downshifted to 2nd in my Accord V6 (auto only) for the 30,000 miles that I had it and had no tranny problem whatsoever. Other people at AccordV6.com that I know use engine braking and shift manually and haven't had any trouble either (except the ones that are stupid and do neutral drops)

The people that restore cars know that the hardest miles you can put on a car are the miles when it's sitting still doing nothing.

Just because it accelerates you everybody seems to think that the engine is only for acceleration. But that's not true. You can just as easily use it for braking and its been done for eons. I do it all the time in my Maxima and I'm going to continue to do it because I know there's no side-effects other than less brake work.

You guys can all do what you want after reading this.

 

That's funny... and very philosophical!

Hey... entropy happens, so you might as well run it as let it sit!

Like I said, if you like doing it have fun. But don't try to make me believe it's OK for the engine and transmission.

All it is is one of those good driving habits that's nice to acquire... kind of like not driving with left foot on the brake pedal, frequently checking rear view mirrors and not slipping the clutch. It just avoids extra wear & tear and possible problems down the road, but no guarantees given.

BuddyWh

 

I think my brakes are great. Maybe they don't suit everybody, but I haven't driven a car to date that has had brakes like this- and I've driven a lot of cars. Maybe I just prefer them. I also have not have had any problems. My last car was a 00 Lincoln LS8. Now that's a car w/sub par brakes. Maybe the cars too heavy, or the disc's aren't big enough...but you will get brake shutter, squeels (sp?), poor brake feel, and soiled pants when you find they don't stop that car very well. I'm off to do some braking drills

 

Hey, is that TSB for the 2002 only? I have a 2001 AE and my front end is starting to shudder a little when I use the brakes.... wonder if mine are warped too!

 

Check the TSB sticky...

BuddyWh

 

Are you sure about that? Where are you getting this information from? Everyone teaches engine braking when you learn how to drive stick. (Not trying to start a debate, just trying to see where you're getting your facts from)

 

dude id rather my brake pads wear out then my tranny and motor.

 

Sorry man! I don't care what you're saying and I'm not going to get into a kids argument with you about this. All I want to see is preeof that it's bad for a car or any other vehicle to use engine breaking. People always post there opinons on this subject and I want to see fact.

I used to tow airplanes at Logan Airport when I used to work for the airlines and I used engine breaking to slow down the 75 to 150 ton aircraft and never heard anything negative about sing engine breaking (when needed).

If you truely drove newer big rigs and buses, you would also know that there is a pneumatic system on the transmission of these vehicles to allow the driver to slow the vehicle without using the brakes.

 

Here ya go:

E = 1/2 m(v^2 - u^2)

Where: E = energy to be dissipated in joules (J)
m = mass of car in kilograms (kg)
v = initial speed of car in metres per second (ms^-1)
u = final speed of car in metres per second (ms^-1 )

Chew on that a while.

The energy has to go somewhere... with an engine and transmission it goes to friction of the working parts, converted to heat and carried off with the coolant. Some is also lost to compressing gases in the combustion chamber but then most of that is regained on the power stroke as the engine is still coupled to the drive wheels.

With brakes, it goes to friction of the pads against the rotors.

That's your proof.

BuddyWh

 

Engine breaking may not be too bad for the engine or the transmission per se but it will definitely wear the clutch faster (through continual downshifting) and personally, I'd rather replace brake pads then replace my clutch.

I had a friend who engine breaked all the time and wore his clutch out in under 60,000 km. The mechanic took one look at it and turned around and said, "you engine brake don't you." In fact, every mechanic I've talked to in the last 5 years has told me not to engine break. It's not worth it these days. Brakes are reliable and cheap. Use them. Only in cases that don't require a lot of downshifting like long descents does using the engine as a brake really make sense these days.

 

bah... im gonna keep doing what i've always done, which is engine break, i always match the rpms so its all good.

 

engine braking is probably just as "bad" as taking your car to redline.

 

Regardless of what some of you think, the brakes on the max are pretty good. Just because some of you may experience rotor warpage, doesn't mean it prevents you from stopping the car in a shorter distance than say, oh, a geo metro. (See, I find a difference between brake components and brake *performance*.)

I've always downshifted down long streches of mountain decents. There's this thing called 'brake fade'. Nothing like having to mash the brake pedal and smoke/glaze your brakes after a long downhill run. (Of course, my worst offense, is downshifting to slow down without my brake lights activating. Like when my V1 starts screaming at me... )

And this is what my owners manual says:

Let all the conspiricy threorists now claim that Nissan just wants you to do this so you'll have to pay for the trans rebuild...

 

From my searches of the Car Talk guys' columns, it doesn't generally look like it's bad (unless you overuse your clutch on a stick shift). Take a look at these relevant hits for example:
http://cartalk.cars.com/Columns/Arch...tember/07.html
http://cartalk.cars.com/Columns/Arch...bruary/10.html
http://cartalk.cars.com/Columns/Arch...vember/11.html

 

shifting to neutral in an automatic is bad when your at a red light and dont feel like pressing the brake? darn - its not like i do a neutral bomb or anything like that.

 

Well I think I've heard enough. I'm going to seriously cut back on engine braking in regular daily driving.

 

Its not bad its actually good because it releaes starin on the transmission...i belive they meant to say that a neutral bomb is bad but it from what my mechanic said at a stop light putting it in neutral is good for the transmission