i've been wondering about this too, its strange. when i have it in L it goes it has 1st and 2nd gear and then i shift to I without lifting off the gas i goes 2nd to 3rd, then the shift to D goes from 3rd to 4rd and then settles down.

 

I believe L is for low gears(ever get stuck in the mud? running through all your gears just makes it worse).
The I is for Incline I think and runs higher RPM.
The D is Drive(overdrive) and saves you gas by shifting more efficiently.

 

L & I?? I have 1 & 2 then D i guess they changed it since the 05s...

 

Our Cobalt's autotrannies are not like older trannies (05 has 1 2 D while 06-up have L I D). "L" holds the tranny in first until redline then shifts into second. "I" is for "spirited" driving and holds the tranny until 4K RPM from 2nd to third shift; it also downshifts as well as upshifting 3-2-1 and, of course, 1-2-3. It won't go into overdrive (4th). Using I makes the engine throttle input changes faster. "D" is the economy position allowing the tranny to upshift quickly into OD for fuel mileage -- but you get no engine braking when you let off the gas. 08's with the instant mileage in the DIC show 99 MPG when you are going downhill with the throttle closed (engine shuts off the fuel, I'm told, in that condition to get the most mileage).

 

I is for intermediate. It should be used when towing something, it provides less shifting back and forth between gears, and low is obvious for the low end power and torque. I dont understand why people shift in there auto cars. You spent the extra money for the luxary of not having to shift and you do it anyway. And not to mention the long term negative effects this puts on a car. You really should not shift in an automatic car if you want it to last.

 

Your description of "I" -- Intermediate -- is outdated. In the Cobalt "I" gives full automatic with 1st - 2nd - and 3rd gear but the shift point at part throttle is raised to 4K RPM -- and it also downshifts aggressively as you slow down. Additionally, If you don't pull it into low and turn off the traction control when you get wheel spin the ECU backs off the timing to reduce power and your acceleration suffers (2.4L cars and 2.2 w/traction control). With the lever in "L" the valve body increases line pressure to support maximum torque from the engine -- it also shifts the tranny into 2nd perfectly at the redline -- no mis-judging on the driver's part. Shifting an automatic tranny does not reduce it's life -- if it did this would affect the warranty and the manufacturers of autotrannys wouldn't provide a way to shift it. I've been driving auto equipped cars for 30+ years -- and I have driven them aggressively while manually shifting them -- never had an auto go out on me. I also owned a 70 Ford for 27 years and drove it nearly every day to work using a B+M ratchet type shifter -- the third owner is still driving it.

 

Now THAT'S the answer I was looking for!! Thanks "Red07SSNA". Any more info you have on it? I enjoyed reading an detailed account of a question that had me shaking my head. And the owner's manual offers little/no explanation.


GTO 1

 

Yea manually shifting an auto is not good for it even if your just doing it for racing purposes. I have found that manually shifting while drag racing actually resulted in slower times. I just got the B&M shift+ kit and installed that for quicker shifting which has resulted in .2 sec faster times at the track and that was b4 i installed the polly bushings. Interested in seeing if i get even better times with them installed.

 

Shifting is bad -- whew, I'm glad you guys mentioned it. Having never damaged an auto tranny in 30 years I better stop doing it cause maybe it will damage it. It's an "Old-Wives Tale" -- you guys are just perpetuating it! "L" is for increasing the internal strength of the tranny by increasing the line pressure. The Cobalt's tranny doesn't shift when you move the lever --it still shifts at pre-determined times -- regardless of lever position!!!!

Red07SSNA added 4 Minutes and 5 Seconds later...

Why do you suppose all the cars with "sport shifters" have them (the ratchet type shifters that you use to bump the tranny up or down one gear at a time). Do you suppose it is the manufacturers way of getting you to manually shift your auto so you destroy it and have to buy another car? Common guys lets get real now......

 

So while driving it doesnt hurt the tranny to shift from drive to 3rd when coming to a stoplight? I do that all the time, I love the sound it makes....

 

I do too...that's why I will keep mine in "I" around town Speed Limit < 45 MPH. Obviously common sense needs to be used -- don't go putting any auto shifter into low at highway speeds!!!!

Nugz -- the ex-YC admin guy?

 

So the answer is: That manual shifting will generally not hurt automatic cars?

 

Yea manually shifting an auto is not good for it even if your just doing it for racing purposes. I have found that manually shifting while drag racing actually resulted in slower times. I just got the B&M shift+ kit and installed that for quicker shifting which has resulted in .2 sec faster times at the track and that was b4 i installed the polly bushings. Interested in seeing if i get even better times with them installed.

thats because you can red line each gear in a manual. since a automatic tranny works completely different than the gears in a manual, it's just bad and causes damage cause its not made to do that. which is why slower times cause the cant react like a manual can after each shift.

 

No, shifting an auto tranny will not harm the tranny. Having said that, the Cobalt's tranny is unlike any tranny from the past -- no matter where the shift lever is positioned the tranny will shift at predetermined RPMs -- but where you have it will affect the performance. Let me explain:

I had an 06 LS and installed all the GMPP performance parts. I came across an 06 SS 2.4L and we squared off twice. I knew the lady driving the SS was trying because we both got wheel spin off-the-line. My LS proceded to "wax" her SS and I thought it was the GMPP performance parts that were giving me the edge (her SS 2.4L was stock - no accessories). Then I got the bug and traded in my LS for my 07 SS 2.4L and had all the GMPP performance parts installed by the dealer before I bought the car. First time I got "on it" I was DISAPPOINTED! My LS would kick the crap out of my 07 SS UNTIL I found out about the traction control. If you leave the shifter in "D" or "I" and start out with wheel spin the traction control kicks in and kills your performance -- and I do mean KILLS the performance. I found that when you have the shifter in "L" and turn off the traction control the performance is there. So when you have that kind of driver next to you at a light that knows the 4 lane turns into a 2 lane and he/she wants to get around you make sure you drop it to low! After the tranny shifts into second gear remember to shift into "I" so it'll go into 3rd gear.

 

Awesome thread and im glad someone felt like shedding light on the subject. I got an auto and i shift it as well. More fun.

 

i do some auto stick driving, i was kinda wondering if it did have any negative effects on the tranny cause i can here some weird whinning sound coming from under the shifter. another thing i have notice while driving in I or L, is that the whole engine and trans seem to move around a lot as you give it gas then let off. i also noticed that the flex pipe on my down-pipe that mounts to the exhaust manifold is out of shape, this may have been caused by the engine/trans moving around a lot. any input there? i will try to get a pic of the part up.

 

Did you see the Redline TV show where they installed an Injen Intake and the GMPP performance exhaust on an 06 LS with SAI -- and then did dyno runs to check the HP increase? During the dyno runs you could see the engine jerking around quite a bit -- almost scary looking! All engines do this because of the rubber mounts. If the engine was secured to the chassis to prevent movement your teeth would probably hurt everytime you drove because the vibration would be nearly unbearable. If your flex joint is distorted have the dealer take a look at it and see if they will replace it under warranty -- and have them look at your mounts in case you have a broken one.

 

hmm well the downpipe i have is off an ss/sc, i replaced the stock one. i may just have to by a nice aftermarket one. i dont think they would cover my ss/sc downpipe under warranty, maybe the motor mounts but not the downpipe. the car only has 6500 miles on it i hope the motor mount isnt out.

 

If you think about it, why did Chevy design the autotranny to automatically shift out of first gear at 6000 RPM (2.2) and 6700 RPM (2.4) with the lever in "L"? Then you can hold the tranny out of OverDrive by keeping it in "I" -- and it shifts 1-2-3 at higher RPMs while in "I" -- and downshifts too.

My point is that Chevy provided you with the capability -- if it was no good for your car then they would not have made it like it is -- you would have only P-R-N-D.

 

Red07SSNA is right.

 

He is VERY knowledgable!

GTO 1

 

ok guys dont bash me...buttttt...i red over all the comments carefully about driving in L.. i actually only the other week started driving like this and is fun as hell especially with my exhaust and intake and wutnot.. sounds great....neway...when im in L and i know its in first but whren i get to around 5000 rpm i just back off bc i felt it didnt go into 2nd and i would switch into I..All im sayin is I have an 06 LT 2.2..... Are you guys positive if its in L once it redlines it will go into second i wont blow my engine?....thats all..but like a 100% positive?

 

Yea i've done it over a hundred times and it will shift perfect to 2nd at 6000rpm while your still in "L" on a 2.2, but it won't go farther than 2nd so you'll have to shift to "I" once your close to redline in 2nd gear.

 

Ditto! Also, the fuel will cut out if you overrev the engine to protect it too. The only way to hold it in 2nd long enough to use the upper RPM power is to shift the lever from "L" into "I". The tranny has a tendency to shift up too early on it's own. The only time you have a potential to overrev with the auto is when you have it in "L" and you need to shift into third

"L" holds 1st until redline then shifts into 2nd and stays there. Also disables traction control.

"I" allows auto 1-2-3 shift (4000 RPM shifts at part throttle) and 3-2-1 downshifts. Traction control enabled. If you have an automatic and need to show a Honda owner which way to go you should shift into "L"...LoL!

"D" is for emissions and MPG, tranny will upshift quickly and you get very little engine "braking" when slowing down. Traction control enabled.

Red07SSNA added 0 Minutes and 30 Seconds later...

He is VERY knowledgable!

GTO 1

I can fool some of the people some of the time......

 

niceee...thnks guyssss...one more thing..when im in L and i go to 2nd and am abou tto shift to I. Should i take my foot of the gas and then shift? or it doesnt matter?

 

No, you do not need to take your foot off the gas to shift into "I" or "D" on the "fly"....or to shift from "D" to "I".

 

niceee...thnks guyssss...one more thing..when im in L and i go to 2nd and am abou tto shift to I. Should i take my foot of the gas and then shift? or it doesnt matter?

 

niceee..gotta about 1 1/2hr drive home today..should be fun

 

But one thing about auto shifting like that is that it kills your gas milage horribly!

I usually only do it at red lights in the middle of the night lol.

 

That's why "D" is for MPG....OD drops the engine RPMS.

 

Damn after reading all htis i am happy i have a manual...lol .... sucks for traffic though

 

Yea but when we get tired of thinking about shifting we can just put it in "D" and drive all day....and our left leg doesn't get bigger than our right leg..lol

 

hahaha lmao

 

does shifting on an automatic really hurt your transmission that bad?
woa!
i better stop!
i'll admit its fun, but i dont want to mess anything up.

but to be honest, it is nice how you get that extra torque, when you start with L