Automatic shifting?

What are the benefits of using the D,1,and the 2 on the auto? I can feel it push harder when it's in the D position but what about the others? And at what speed is it not safe to shift? Hate to sound stupid but I am!:lol:

Originally posted by Lilbear
What are the benefits of using the D,1,and the 2 on the auto? I can feel it push harder when it's in the D position but what about the others? And at what speed is it not safe to shift? Hate to sound stupid but I am!:lol:


never race in OD,

use D
never manually downshift

use 1 and 2 when you want to stay in that gear.
id use 1 and 2 for autocross or burnouts a the staging lanes.

snow too i guess

Originally posted by Lilbear
What are the benefits of using the D,1,and the 2 on the auto? I can feel it push harder when it's in the D position but what about the others? And at what speed is it not safe to shift? Hate to sound stupid but I am!:lol:

When driving around town leave it in D. 1 means that the tranny will not shift out of 1st gear. 2 means that the tranny will only be in 2nd gear and will not shift out. D means all gears but your overdrive gear. (D) means all for gears, I only use this on the freeway, and use D for all of my city driving. Some will say to always leave it in (D) but I've always driven my cars like this, and have had zero transmission problems.

Benefits as opposed to what?

As far as I know, the only difference in using those different option is the number of gears it will use: D=3 gears, 2=2 gears, 1=1 gear).

I don't think there is be any real difference in performance.

The lower gears you use, the higher rpm's you are running and the more power/torque (to a certain extent, of course) you have available. Also, the tranny will downshift faster and therefore it feels/is a bit faster.

There is no difference in standing start, though.

If somebody with better info proves me wrong, then I'll stand corrected. :D

Later! ;)

TS

I have no idea why you people drive like that..

In my 4L60e, i ALWAYS raced in OD.. I drove all day in OD and that is the way the manual suggests it be done.. Not only that, but anyone that I know that is a "Tranny guru" has said the same thing.

The tranny is electronically controlled.. it will choose the best gear for the job.

Depending on what gears you've got (2.73's or 3.23's) you may find that it's better leaving the car in Drive vs Over-Drive for a lot of your driving. Like you said, it "feels" like it's got a little more power, and that's because you're keeping the revs up and the engine is more in its power-band. Often times I won't put the car into OD until I've hit the highway.............with 2.73's it's just not necessary?!:rolleyes: AND, keeping in D will prevent excessive up/down shifts;). With lower gears though (even factory 3.23's) I'd say it's probably best just to leave the shifter in OD, but again, in town, or in heavy stop-and-go traffic, there's nothing wrong with holding the car back in a particular gear for a while:cool:.

2 things..... First Capn Pete, I couldnt agree with you more. And 2nd, 95GRNZ when the shifter is in 2, that is only 2nd gear not 1st AND 2nd. Try it sometime. Why GM did that I have no clue......

Originally posted by Aklaim
when the shifter is in 2, that is only 2nd gear not 1st AND 2nd.....Why GM did that I have no clue......
I'd say it's so that there's a little less torque to the back wheels in case you want to start in slippery conditions?:confused: But otherwise I'm at a loss too!:D

Originally posted by treyZ28
never manually downshift
Why?

Originally posted by Aklaim
2 things..... First Capn Pete, I couldnt agree with you more. And 2nd, 95GRNZ when the shifter is in 2, that is only 2nd gear not 1st AND 2nd. Try it sometime. Why GM did that I have no clue......

Really??? :eek:

Learn new every day. :D Maybe I should try that one of these days... :think:

that's their second gear start program, it's made for snow etc.

Originally posted by chevy qc
that's their second gear start program, it's made for snow etc.

Now that you mentioned it... I think I might have heard about it at some point.

Tried this morning and sure enough: started from the second gear. ;)

Somebody correct me if I'm wrong again, but I am pretty sure that wasn't the case in my LT1... :think:

TS

Driving around in D/3rd in traffic doesn't do anything other than eat up gas ... yeah it feels faster because the TC is never locking up and you are stay high in your rpm band. OD/4th is your gas saver, it's where the TC locks up and driving in traffic is the worst on gas milage ... staying D/3rd will only exaceberate it.

If you are in traffic and you need to to down shift, all you have to do is double tap the accelerater and then floor it. The transmission will unlock and drop down to the appropiate gear.

D/3rd is good for your performance driving, when you don't want it to lock up ... ie road racing/whipping through the mountains ... personally I don't consider driving around in traffic performance driving.

To answer the original question ... OD - all routine driving, your gas saver ... D - performance driving, road racing, canyon carving drag racing ... 2 - when you need torque and autocrossing (depending on the course youll never get much over 60mph, no need to let the tranny shift into 3rd) ... 1 - ditto 2 on the torque.

Good Luck

Originally posted by 99blackSS
Why?

I dont know about you, but i dont have a manual valve body :ppp


Originally posted by Aklaim
2 things..... First Capn Pete, I couldnt agree with you more. And 2nd, 95GRNZ when the shifter is in 2, that is only 2nd gear not 1st AND 2nd. Try it sometime. Why GM did that I have no clue......

Are u sure? I'm almost 100% confident you are wrong unless there is some differance in Lt1/LS1 which i doubt.

At the track, the car in front of me broke down and i was still in 2nd frommy burn out. 10 min later i roll upto the line forgetting i'm in 2nd.

Launch and around the 1/8th i kicked this **** out of the rev limiter.

I KNOW i didn't start in 2nd because i was RIGHT next to a 12 second camaro till i hit the rev limiter. I also pulled a 1.9 or 2.0 60 60ft which isn't happening in 2nd gear start. My mph also looked ok




Why would they put an "2nd gear start" button in the firebirds if this was true?

Originally posted by V6toZ28
Driving around in D/3rd in traffic doesn't do anything other than eat up gas ... yeah it feels faster because the TC is never locking up and you are stay high in your rpm band. OD/4th is your gas saver, it's where the TC locks up and driving in traffic is the worst on gas milage ... staying D/3rd will only exaceberate it.

If you are in traffic and you need to to down shift, all you have to do is double tap the accelerater and then floor it. The transmission will unlock and drop down to the appropiate gear.

D/3rd is good for your performance driving, when you don't want it to lock up ... ie road racing/whipping through the mountains ... personally I don't consider driving around in traffic performance driving.

To answer the original question ... OD - all routine driving, your gas saver ... D - performance driving, road racing, canyon carving drag racing ... 2 - when you need torque and autocrossing (depending on the course youll never get much over 60mph, no need to let the tranny shift into 3rd) ... 1 - ditto 2 on the torque.

Good Luck

first off-
are you SURE the TC doesn't lock till od :think: ? some people verify this. put it in D, drive down the highway, keep foot on gas and tap brakes. do RPMs jump 100 -200rpms?


secondly, the whole point is to reduce wear and tear which comes from uneccisary shifting. I dont twant my tranny constantly coming in and out of OD to save 200 rpms. I just pop it into OD on the highway.

Originally posted by treyZ28
Are u sure? I'm almost 100% confident you are wrong unless there is some differance in Lt1/LS1 which i doubt.

At the track, the car in front of me broke down and i was still in 2nd frommy burn out. 10 min later i roll upto the line forgetting i'm in 2nd.

Launch and around the 1/8th i kicked this **** out of the rev limiter.

I KNOW i didn't start in 2nd because i was RIGHT next to a 12 second camaro till i hit the rev limiter. I also pulled a 1.9 or 2.0 60 60ft which isn't happening in 2nd gear start. My mph also looked ok

Why would they put an "2nd gear start" button in the firebirds if this was true?

YES.....I'm 100% sure that when in 2, that is second gear and ONLY second gear. 95GRNZ tried it himself this morning. It is different between LT1 and LS1 cars. This is a LS1 forum, so I am speaking strictly on what it does on a LS1 tranny.

Originally posted by Aklaim
It is different between LT1 and LS1 cars.

Ha!!! Thanks for confirming I'm not losing my mind! :D

Like I said, I was pretty sure in my old LT1 when in 2 it started from 1st gear and shifted only to 2nd.

Trey: Go and take ride in an LS1 and see it yourself. ;)

Originally posted by Aklaim
YES.....I'm 100% sure that when in 2, that is second gear and ONLY second gear. 95GRNZ tried it himself this morning. It is different between LT1 and LS1 cars. This is a LS1 forum, so I am speaking strictly on what it does on a LS1 tranny.

Ok, just checking :)
I wouldn't expect you to specify "on LS1" in the LS1 forum :p. I was just asking if there was a differance.


My next car is an LS1 and 6spd. I'll pick any damn gear i want.
I want to try this autocross stuff. An Ls1 with an aluminui block an top end power is what i need for autox

This question was asked in the November issue of GMHTP magazine 2002 to some guy (ask eric!) that has worked in GM overdrive trans for 7 years.

Q.- In a 700-R4 or 4L60E, is it better to shift manually in a drag race or to let the trans shift automatically?

A.- In a street/strip application, the trans should be set upto shift automatically in the "overdrive" or "drive" position. When you manually shift it, there's a delay in pressure rise. You push the lever and it won't respond right away because there's not enough line rise. You can burn the trans out shifting manually because there's not enought pressure to hold the clutches.

I had a friend who screwed his trans twice cuz he kept shifting manually in his a4. Plus he was using nitrous.

Is the 4l60e that makes sense. The tranny is elctronically controlled and when shifting there is a huge delay. But on a 700-r4 tranny, manual shifting is the best way to stayinyour power band. And I have had zero tranny problems, and i manually shift my 92 all the time.

i ran into a guy with a 98 A4 Z28 (identical to mine except for an airbox lid) who claimed that shifting the 4L60E manually bought him a .19 sec improvemtn in the quarter. i dont know whether to believe this but he mentioned something about the stock programming shifting at 5700 RPM at WOT where as the motor is good up to the 6000 RPM redline. i haven't tried this because i just got my 98 and im still terrified to beat on it (wish i could say the same about my old LT1) is there any truth to this??????

from what i hear from 6spd guys- the best stock shiftpoint is the highest you can shift without hitting the rev limiter.

so yeah, if you can get another 200-300rpms out of it, it could help. manual upshifting isn't a big deal, down is

I know lots of guys around here locally who have tested the D vs OD thing at the 1/4 mile track and there was NO difference in performance(ET's & MPH). And many guys on the other LS1 boards(LS1.com/LS1tech.com) have tested this out and come to the same conclusions.

Driving around in D will only eat up more gas bring on additional wear to the engine with the higher rpms around town. It's not really that bad, but I'd just recommend leaving it in OD unless you have a reason for putting the car in D.

BTW Trey, a stock-cammed LS1(with bolt-ons or not) should be shifted around 6,000 rpms which is right before the set 6,250 rev-limiter.

Mike

2002 M6 Z28

Originally posted by 94ZRiCeKiLr
i ran into a guy with a 98 A4 Z28 (identical to mine except for an airbox lid) who claimed that shifting the 4L60E manually bought him a .19 sec improvement in the quarter .........................................i haven't tried this because i just got my 98 and im still terrified to beat on it (wish i could say the same about my old LT1) is there any truth to this??????
I don't think there is any advantage to "manually shifting" the 4L60E:o, and I've run back-to-back runs with greater than .19 second differences, and usually it all starts within the 60', not as much to do with shifting?:think: (although I do understand the fact that you want to rev the engine higher than ~5700/5800 rpm). Because of the delay in the shifts though, it's hard to know exactly when to "shift" so that the tranny shifts at the right time:rolleyes:. Transmissions like the TH350 in my '81 did benefit from manually shifting though. When I'd shift, the transmission would shift, so it was easy to hold the car in each gear and know it would shift when you wanted it to...................also, without a rev limiter was even better!:D

Also, I don't like the argument that driving is D is going to be "hard on the car, hard on gas, etc., etc.":no:...........think about transmissions before we had the 700R4 --- there was no Over-Drive?!:p I know that it's there to provide better fuel economy, but I don't think it will make much difference until you're on the highway. And what about guys running with either stall converters or lower gears? Won't they also speed up the wear-out process throughout the driveline?!
..............sometimes there's a price to pay for performance!;)

cptn-

I guess if you perfect it (cant really do it with a stock guage) 300rpms of powerband could really help...


as far asracing in D vs OD-
it wont make any performance differance! you weren't going into OD(well 95% of us) anyway :p. It might firm shifts up, i dont know. i never raced in OD to compare. Its not to reduce shifting time, but a firmer shift under loan is just healther for the trans from what i'd heard.

driving around in D vs OD-
I just do it to save the car another pointless shift. its going to come RIGHT back out of OD any in a few seconds anyway.
gas milage shouldn't really varry D vs OD IN THE CITY. At 40mph, there isn't much of an RPM differance. But the constant changes in speed (accel and decel) force shifts. less shifts is good.

I also agree with Trey on the D vs. OD issue. Personally, it kinda pisses me off when I'm just cruising and it wants to shift at 45mph or so into OD when it's just gonna downshift in a few secs anyway. My dad got his 97 Silverado brand new, and it now has just over 180,000 miles. Since he got it he has driven it in D until about 50mph, then shifted into OD. To this day he still has had 0 tranny problems, so it can't be hurting anything.

Here's what the Owner's Manual has to say about all of this...

AUTOMATIC OVERDRIVE ((D)): This position is
for normal driving. If you need more power for passing,
and you’re:

Going less than about 35 mph (55 km/h), push your
accelerator pedal about halfway down.

Going about 35 mph (55 km/h) or more, push the
accelerator all the way down.
You’ll shift down to the next gear and have more power.

DRIVE (D): This position is also used for normal
driving, however, it offers more power and lower fuel
economy than AUTOMATIC OVERDRIVE (
).
Here are some times you might choose DRIVE (D)
instead of AUTOMATIC OVERDRIVE (
):

When driving on hilly, winding roads.

When towing a trailer, so there is less shifting
between gears.

When going down a steep hill.

SECOND (2): This position gives you more power but
lower fuel economy. You can use SECOND (2) on hills.
It can help control your speed as you go down steep
mountain roads, but then you would also want to use
your brakes off and on.
If you have a 5.7L V8 engine and manually
select SECOND (2) when you start the vehicle,
the transmission will drive (and stay) in second gear.
You may use this feature for reducing torque to the
rear wheels when you are trying to start your vehicle
from a stop on slippery road surfaces, or for preventing
the transmission from downshifting into FIRST (1) in
situations where a downshift would be undesirable.
NOTICE:
Don’t drive in SECOND (2) for more than
25 miles (40 km), or at speeds over 55 mph
(90 km/h), or you can damage your transmission.
Use AUTOMATIC OVERDRIVE (
) or
DRIVE (D) as much as possible.
Don’t shift into SECOND (2) unless you are going
slower than 65 mph (105 km/h), or you can
damage your engine.

FIRST (1): This position gives you even more power
(but lower fuel economy) than SECOND (2). You can
use it on very steep hills, or in deep snow or mud. If the
gearshift lever is put in FIRST (1) gear, the transmission
won’t shift into first gear until the vehicle is going
slow enough.

what a load of crap-
it doesn't give you ANY more power. my transmission can kick down to first on its own and have the same amount of power.

The point is, you dont want to shift a whole lot under load (ie hills, towing ect)

if you are only going to be in OD for .8 seconds and only lower rpms by 200, why even bother with all the additional wear and tear.

this is more common sence than tech

I am not accusing any one of lying but, I find it hard to believe the track times are the same when manually shifting and when just leaving it in drive. I think manually shifting the auto (at least the 4L60E) at the track would get a little bit higher times because when I manually up shift it takes a second for the car to shift into the next gear. The only time is manually shift it is when down shifting to slow down.

I downshifted from 3rd to 2nd (by accident) at about 3000 rpm the computer would'nt let the tranny go in to 2nd.





NICK

Wow.... old thread.

Gonna move this one over to Drivetrain Tech. Might help or at least encourage more discussion over there.

-Mindgame