worldwidechance

like rolling up to stop lights?

would it be better to put it in neutral and just use the brakes?

highwater

That save me lil mileage but mines a stick. Prob would word also for auto

TheJerm

I always down shift. The computer knows when its engine breaking and significantly reduces and amount of fuel sprayed into the motor. I always joke with friends that i get much better gas mileage in the mountains than i do in the flatlands.

Back when mine was 2wd i would get 21-23mpg, now i get 18-20mpg with 3.55 gears. Last trip i made to GA i got 21mpg again and i think it had alot to do with engine breaking down the inclines.

Plus I dont think I've every done a break job on a manual car I've owned.

Willys55

saves wear and tear on the brakes when you down shift......

MonacaYankee

30$ brakes or a new transmission. I'll gladly use my brakes.

kyledye25

x2. I also think though that would be getting worse gas mileage by down shifting. I know here in western pa I just throw my car in neutral down a hill or on my to a red light. Mines a 5 speed metro. If I do that I'm always over 45 mpgs every tank. If I always leave it in gear and down shift to red lights and stuff I drop a little below 45.....usually 42ish. now the XJ is an auto and havnt done that. Not sure I want to in an older vehicle with an auto. Just let go of the gas and brake. The rpms stay low any ways.

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TheJerm

Down shifting is just like up shifting, its not gonna ruin a trans.

The reason i down shift is so i dont have to come to a complete stop at red lights when i can help it. I always laugh at people, particularly women, who are either full throttle to the next red light then slams on their brakes, while i just slowly cruise by them as the light turns green. Coasting down inclines is fine when you dont have to stop at the bottom or dont start speeding up alot but downshift helps out alot on real steep hills/mountain.

I'm too lazy to search the webs for it now, I lost my bookmark somehow, but it was shown with lt1 sbc's that the duration that injectors are open during engine braking is less than that of idle. Which means its using less fuel. Might not be the same for all car makers. Although with modern cars using fully computerized systems, it makes sense for them to cut off fuel during engine breaking.

MonacaYankee

I'm talking about people who downshift on their way to a red light. The only time you might need to downshift is going down a mountain. With an auto tranny, they often jerk into gear while downshifting. I'd rather use my brakes and let it shift itself instead of forcing it. I feal that it increases the life of a tranny if the shifts are always nice and easy.

Kyle 4x4 4life

With an auto i totally agree...but a manual is a whole different story to me...i downshift everytime i need to slow down in a manual...90% of the time i never have to touch the brakes...real money and time saver being my pickup has drums all the way around.

TheJerm

Yea downshifting an auto during regular driving is retarded. I didnt know people thought this was about auto's...

Troth

I most deffinetly used Neutral in Boise last summer when stuck in traffic and not moving. Jeep was hot! and I needed to reduce load, helped some. I try to only downshift on a decent hill..... wear and tear on tranny and such

Gee oh Dee

Moved to chat.

Those who suggest doing it in an auto are crazy.

With a manual trans, you aren't putting any added stress on the trans, except for the syncros unless your not RPM matching. its the clutch and the rest of the driveline that would feel the stress. If you don't RPM match and you just dump the clutch, your forcing the syncros to do double duty, which will cause them to wear prematurely. Its also forcing the clutch to work extra hard as it has to slip a bit until the RPMs match the wheel speed.

If you don't RPM match to keep the stress off the driveline, then your tires are gonna bark, chewing the rubber early.

And I'm 99% sure that the injector pulse is SHUT OFF while under deceleration in an engine braking situation. Therefore getting VERY SLIGHTLY better gas mileage. But it equates out to be a fraction of a percent.

So you really won't notice the gas mileage at all.

Troth

Yes, but there are instances that you NEED to down shift. case in point, the Rockies. You will ruin your breaks and possibly start a fire if you dont downshift in an auto

Gee oh Dee

I agree, but I don't want some members here to get the idea that they should do it on a daily basis with an auto trans.

It won't last long doing this on a daily basis. Unless built to do so, and the stockers aren't.

Troth

X2