Switching Gears with Automatic
 

ok, so i've been seeing a ton of posts about this lately, and figured i'd give it a try... i noticed a VERY surprising difference when i started in L, switched to I right before redline, and then popped it into D... i was smiling the whole time, since it was so much quicker than keeping it in D... my question... is this safe, or bad for the car? it is not something that would be done all of the time... thanks guys

Doing it some won't hurt... but all the time will put more wear on the tranny... do the 2.2's have a tranny cooler?

Also... it kills your gas mileage....

i don't know about the cooler, but you're right about the gas mileage... if anything, i would do this every now and then... but damn... last night, i did it from a stop light (not racing, just me on the road) on the highway, and the car was QUICK!! but at the same time, that 10 second stretch before i put it into Drive the DIC gas milage went from 30 to like 26...

its not good for the car. but if only do it some of the time it's not too bad.

Manual Shifting when accelerating doesn't really hurt anything. But down shifting can cause pre-mature tranny wear.

look into getting a shift controller, then you can have full control of the gears (basically driving a manual without a clutch)
theres an engineer that could probably give you a cheap controller design that hangs around on the gm delta forum.

i think in the automatic 1/4 mile thread in racing we confirmed that to get the best time out of the auto to launch in L it shifts once then on 3rd you throw it into D, but we could be wrong

i always thought it was bad for the car....wait no thats right....i dropped the tranny in my old maxima from doing this, dont do it, get a stick if you want to race the car ;)

I repeat.

does any1 know of any companys that make shift kits for our tranny/motor? Sorry Im fairly ignorant when it comes to transmissions...

Unless the car has a semi automaic mode, then you are just fucking around for nothing and are not holping the trannys lifespan. It's called Automatic. If you want to play street racer, get NFSMW or trade in the car for a MTX.

I used to manually shift my 3speed auto (no overdrive) '96 Toyota Corolla... I would be the hell out of that thing... I would always downshift into second... you really needed to to take advantage of all 100hp.

-Rich

haha :twothumbs

talk to ipt transmission i think halfcent used them for his tranny

quick question is our trans # 4T40E???

4t45

What am I looking at here? Mechanical malfunction or stupidity of driver?

thanks

the same tranny is used in the 3500 V6 Malibu's.....hmmm

Its a 4T45E (4 speed, transverse, 45 is the like the power handling capacity rating or something, electronic), code MN5. The shifting is done completely via computer control, no shifting solenoids in the unit.

GM's literature about the Hydramatics for 2005

IPT does in fact make a manual shift unit for the car. In fact, is it switchable between normal drive and manual drive. The two things I don't like about it are 1) its kindda ugly, just a plain metal box with some buttons on it, 2) its one of those devices that gives you the power to really break the transmission if you push the wrong gear button at the wrong time.

the malibus that have this tranny have the manual shift option right on the shift, I know, I have one.

I believe you are looking at a Diff..

That's obviously a manual transmission.

I'd chalk it up to stupidity of driver before I'd claim a problem with power handling.

You can build a bullet proof transmission (auto or manual) but with enough neutral drops/clutch dumps you can kill any diff.

P.S. The 4T45E is a dual axis transmission with an output stack (including diff+housing) that will easily cross the width of many small passenger car sub-frames. Yes its a twitchy piece of engineering as far as power handling is concerned, but the PCM is programmed with specific algorithms to increase transmission life. This includes manual down-shifting to engine brake on downhill grades. Completely expected and normal operation as far as GM designs their automatic transmissions.

I've manually downshifted my T60E for years when the need arose and have had 0 problems. Factory transmission build at 114,000 miles and still as strong as ever.

The 4T45E is derived from the 4T65E which took many of its design cues from the 4T60E... it just employed a larger diff and slightly larger clutch surfaces. Comparing the 4T45E to the 4T60E, the 45 has slightly smaller clutches but an extra plate or two where it counts. The diff casing is essentialy the same as the T60E with a smaller planetary setup.

I just liked the picture actually..

Serves me right for caring. :rolleyes:

Sorry man, Pictures are cool.

So is random posting to increase your post count, but you dont' see me doing that.....

wow, tons of responses, thanks guys...


for those who say it's not good to occaisonally shift an automatic, why is there lower gears then? what is the purpose of having a "L"? i mean why would you need to ever put the car in first gear?

also, i found a TON of articles online that say that with the newer cars, they build the trannys so that they can handle the stress of changing gears... so now i'm in the same boat as i was... some people saying it's ok, some people saying it's not... does anyone have a definitive answer that's based on fact, not an opinion?

thx

If it were supposed to happen, it would have 1234.

IMO, let the car do and run within the design limits that it was intended for, if it wants to shift let it. The only thing I can see that would be usefull is if you are about to pass someone and want to downshift for that extra time and speed. Basically, in that senario, you probably should not be passing either. :)

First of all I don't really know much about the strength of the automatic transmission but I also up and down shift it ocasionally.

Now my question is:
If it is bad to downshift an auto why does it say in the owners manual that you can downshift while going down or up hills.

you can do it, and doing it in NORMAL driving occasionally shouldn't do anything bad to it. performing constant full throttle upshifts and downshifting at high rpms/or multiple gears would introduce a much greater shock though, and typically higher shock loadings do more damage.

I gotta tell you guys I went to Moroso last week and tried shifting from L to D at redline and my time was a full 4 tenths slower then my own little powere launching technique. THe only problem was I didnt shift into Intermediate (I) I went straight to D at redline. I ran 17.1 @ 80mph with that run and when I launched it my own way my best has been 16.7 @ 81mph. I hate traction control and thats wat sucks about the auto, especially when drag racing.

Steep Downgrades. Steeper than you'll probably ever see in your lifetime. hehe. It's to keep the car from racing out of control and to keep you from burning up your breaks on a long steep downgrade.

I'm no expert but I'll say you're going to put more wear on the tranny than if you leave it in Drive. That's really just common sense talking though. The harder you drive it, the more wear it's going to take.

actually there are solenoids, they are triggered by your PCM. i didnt take the time to read that link but im sure its hidden in there somewhere.

I do it all the time...

So anything to turn an auto to a paddle shift or a push button shift? On anycar?

i dont know if there is anything for our cars yet but they are out there. i had the idea of making one to sell that didnt seem to generate too much interest.