so i drive an auto tc and i was wondering if down shifting is bad for the engine. for example, id be on the freeway on D4 going around 70...then i put it on D3 and the engine shifts down and then when i gas it the power is INSTANT...its amazing while changing lanes....anyways, how bad is this for the engine?

 

I'm not positive, but i messed up my mom's automatic tranny on her new buick station wagon by downshifting when i first learned to drive as a teenager. I took it down to get checked out, and the dealer told me it would cost around 2 to 3 THOUSAND dollars to repair/replace, but the car was still under warranty(I found out later), so my cost=$0.00 Woo Hoo! But to answer your question, I think it does more harm than good. Just use your brakes-their cheaper to fix and replace.

 

Actually if you know how to downshift and when to, its better for your engine AND for your brakes. Downshifting is quite simple but takes a while to get a hang of cuz you don't want to just downshift and then release the clutch right away. You try to keep your RPM's up so you'll get a smoother ride as well. For my xB, normally when I come to a stop light and I'm going 50mph on 5th gear, you can shift to 3rd, gas a lil while your foot is still on the clutch (so your RPM's would reach about 3,800 - 4,000) and release the clutch. I think for me it helps a lot. You have to be somewhat alert too cuz you don't want to rev too high into a gear or your car will jolt forward and you don't want to downshift to a low gear at high speed.

My Downshifts.... My xB
60mph > downshift 4th gear > around 4000 rpm.
50mph > downshift 3rd gear > around 4000 rpm.
35mph > downshift 2nd gear > around 3,500- 4,000 rpm.

I rarely downshift to first cuz by the time you reach second... you can easily pedal on the brake and slow down... so its pointless. Plus... its weird how if your moving, it gets stuck and won't let you into 1st gear. Hmph. Anywho... watch some drifting videos or initial d (not for the mountain running, but for the foot work) Hope this helps =)

 

He's talking about downshifting an auto.

It's a lot worse on an auto than on a manual. On an auto, just stomped the gas and usually the engine will downshift by itself. If not, than you don't need to downshift anyways.

Besides, the tC has enough torque and horsepower in the entire band to pass with ease. I don't see why you be beat'n on poo' lil tC o' yous...

 

really?...because i down shift the ____ out of my auto

 

downshifting in an auto is the same as if it were manual, just make sure you respect the max speeds allowed in each gear/position if your doing 70 dont drop it to low or something bad will happen. d2 is supposed to run to 67 or something like that but i wouldn't take it higher than bout 50 to 55 max, all the speeds are listed in the owners manual ( i believe it actually has a page that talks about downshifting or engine braking however you may call it).

 

Perhaps I should've said more risky. There are only four gears on an auto and five gears on a manual meaning it's easier to downshift into something pretty bad. I was in my friend's car when he did it once cause the damn thing's brake line broke. Shifted down into the redline, had to shift down again to brake in time and had a lot of problems afterward. He's getting a tC now cause I convinced him

 

Doesn't the tC come with a tach? Use it!!!

 

Why didnt you just buy the 5 speed if you like to shift so much?

 

There's a big difference in being ABLE to do something and HAVING to do something. The auto is just more versatile. I can drive it to get most of the benefits of a stick, but I can also not care if I don't feel like worrying about it. There's lots of time when downshifting helps, but I don't need it every moment of every drive...

 

it may not be especially BAD for the auto transmission (jury is still out on that), but we can agree that it's certainly not GOOD for the transmission.
One of the reasons that the tC's automatic transmission gets better fuel economy than the manual (by just a bit), is that today's automatic transmissions are more sophisticated and efficient than cars were even a few years ago. The tC has an electronically controlled automatic transmission with intelligence, it works with your variable valve timing to monitor the engine load.
I'm not a gear-head, but normal automatic transmissions change gears based on the engine load and speed. The tC has a hydraulic lock-up that limits the loss of engine power due to slipping at medium and high speeds. In addition you've got the uphill and downhill shift logic that limits "gear-hunting." Downshifting your automatic yourself circumvents the sophisticated tech that's built into your Scion to give you the best balance between emissions, fuel economy and performance. Downshifting basically uses your engine and the components of the transmission to slow the car. Anyone who's taken high school physics knows there's no such thing as a free lunch, that energy goes somewhere. The most expensive brake job is still better than the cheapest transmission work.
My dad used to say "don't confuse me with the facts, my mind is made up." I doubt I'll change anyone's mind. I'm just really proud of my Scion, let's just agree that the tC is a hell of a car!
PS: my feelings get hurt easily, so go easy on the bashing!!!

 

i downshift my auto alot too....

I put 60k miles on my last car (02 Hyundai Accent), and did alot of downshifting in that auto too. Didnt seem to hurt it any. Not taking RPM's over 4k is good advice though.

 

First of all, it's not doing anything to the tranny that the tranny isn't made to do - shift gears. Secondly, it's an electronically controlled tranny, you aren't "shifting" it when you move the handle, you're just telling the computer which gears it can use when it shifts. You're just capping things off at 3 or 2, etc...

Using your physics, wouldn't you say that it would be better to spread that energy across the drivetrain or isolate it to the brakes? I'm just playin' Devil's Advocate here... It's not a trade of "brakes" or "tranny", when it's done right it won't harm your tranny and will actually prolong your brakes.

Grade logic is useless if traffic is the reason you need to slow....

If you know how to drive a stick correctly and that includes engine braking, then you should be able to apply those same concepts to an automatic tranny. Just remember that it's auto tranny, not auto-pilot...

 

I agree that new autos are much more efficient now than a few years ago. I think manuals are still better though with the same gearing. Doesnt the auto tC had higher gearing (lower number)?

 

.....OH.


I always thought popping it into D3, 2, and whatnot was physically forcing the tranny back into the respective gear.

/Mah baaaaad.

 

I called a scion tech. with this same question a couple of months ago. He said it doesn't do anything bad aslong as you dont keep it at a super high rpm for a long time. As long as you treat it as you would do a manual, you can shift it up and down as much as your please.

 

you can not downshift on automatic, like enigmon said, it messed up the tranny. plus your using up your transmission fluid...


theres no point in downshifting for more power, when you STOMP the gas the ECU will automatically down shift itself!


its an automatic, you got no control over your transmission, the computer decides how fast it can go pending on how much you press on the gas pedal.

 

dude, why didnt u just get a 5 speed.

 

You can downshift an automatic. If I'm in Drive, in 4th gear, and shift into 3rd, the car will shift into 3rd gear. Is that not downshifting? You dont mess up the tranny at all doing that. If you dont believe me, call a scion tech yourself. How exactly are you using up transmission fluid?

I dont downshift for more power, I down shift because I want my car to stay in that gear for whatever reason. You are so wrong about controling an auto that its not even funny. The car will go into whatever gear I select. If im going 50 in 4th gear, then pop it into 3rd it will go there. If I decide to pop it into 2'd, it will go there too.

 

YOu know, instead of knowing and having to hassle with downshifting your automatic, there is a solution to this...

its called 5 SPEED