Torque Management IN ACTION!
#14
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haha ok I'll explain a little about what you're looking at. GM, in their quest to provide more power with less cost, built engines too powerful for the transmission they're bolted to. The result is Torque Management. The PCM is designed to cut the spark advance (and fuel) just before shifting at redline so the transmission doesn't get the blunt end of all the torque and throw its gears all over the road. If you look at the picture in the second set of lines you'll see a sharp drop in spark advance. If you relate that to the other lines you'll see thats just when it was about to shift. The point is lots of people, including me, were a little clueless on the complete impact of this. I always thought your 1/4mile times would be more affected by the sudden drop in power but as you see it recovers so quickly the losses become almost null.
#15
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Is this on your car? If it is, then it'* just the shift timing, not actual torque management really.
The torque management complaing about here, is on series II L67. They can produce about 330 Ft/lbs peak if they weren't capped. This is a constant manaegement.
Makes ya wonder why our torque curve is so flat doesn't it.
The torque management complaing about here, is on series II L67. They can produce about 330 Ft/lbs peak if they weren't capped. This is a constant manaegement.
Makes ya wonder why our torque curve is so flat doesn't it.
#16
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as read on pontiacserver.com:
A little history on the 4T60 used in FWD GM vehicles.
The THM440-T4 was introduced in 1984 on the new GM
full sized luxury vehicles (Oldsmobile Regency 98, Buick
Park Avenue, Cadillac Sedan Deville - remember the logo
on the trunk lid "4-Speed Automatic"). This transmission
was basically the THM125-C with an overdrive added on.
The original 440 was not very reliable. Many changes
were made the first 3 years. Areas that suffered many
failures were torque converters (clutch rivets), 2nd
clutch housings, 4th clutch area, final drive.
When the Cadillac Allante was introduced, the 440
would not handle the torque of the V-8, so a special
version known as the F-7 was developed. It included
special sprockets, heavy duty final drive, special
fourth clutch, etc. A rare but solid transmission if
you can find one.
By 1988 the quality was better, but to make the
440 (now called the 4T60) a world class transmission,
electronic controls were added. The new transmission was
coded F-31 and became known as the 4T60-E. The 4T60-E was
phased in from 1988 to 1990. You can tell by looking at
the bottom oil pan - it will be stamped with "4T60-E".
This transmission has much better reliability. By the
1991 model year, all FWD Overdrive transmissions were
the 4T60-E model.
As a side note, with the introduction of the
Northstar V-8s, a new low volume transmission was
developed for these applications. It is known as the
4T80-E. Very durable but very expensive, about 80%
higher in cost than the 4T60-E. Also 60 pounds
heavier.
With the introduction of the Supercharged 3800,
a few modifications to the 4T60-E were made. The
biggest change is the final drive unit, which is of
heavy duty design.The transmission still can't
handle the full torque of engines such as the SC 3800
and the DOHC 3.4L V-6s at redline during shifts. GM
utilizes Engine Torque Management to maintain
reliability. This consists of controlling engine rpm
and engine torque (through timing and fuel) during
shifts. That is why the SC 3800 and DOHC 3.4L do
not shift at redline at WOT.
For the 1997 model year, GM introduce the 4T65-E.
This transmission is a heavily reworked 4T60-E design
which includes such features as a 258mm torque converter
instead of 245mm, twin chains and special sprockets for
noise, Electronic Line Pressure (ELP) for ECM control
of pump pressure to better regulate shift quality,
revised fourth clutch, revised second clutch housing,
and many other improvements to reliability. The first
applications to receive the 4T65-E will be the
SC 3800 V-6 and the DOHC 3.4L V-6 to minimize the need
for torque management. The phase in will be three
years and will be complete by model year 1999.
The biggest cause of failure of the original
4T60 (440) is heat. [snip of restricted info] Through
control of shift points and torque converter lockup,
tranmission temperature can be controlled. There is
a temperature sensor in the transmission for the ECM
to monitor. This shows the STRONG recommendation
to add and external air/oil transmission cooler
for 4T60 (440) equipped vehicles.
A little history on the 4T60 used in FWD GM vehicles.
The THM440-T4 was introduced in 1984 on the new GM
full sized luxury vehicles (Oldsmobile Regency 98, Buick
Park Avenue, Cadillac Sedan Deville - remember the logo
on the trunk lid "4-Speed Automatic"). This transmission
was basically the THM125-C with an overdrive added on.
The original 440 was not very reliable. Many changes
were made the first 3 years. Areas that suffered many
failures were torque converters (clutch rivets), 2nd
clutch housings, 4th clutch area, final drive.
When the Cadillac Allante was introduced, the 440
would not handle the torque of the V-8, so a special
version known as the F-7 was developed. It included
special sprockets, heavy duty final drive, special
fourth clutch, etc. A rare but solid transmission if
you can find one.
By 1988 the quality was better, but to make the
440 (now called the 4T60) a world class transmission,
electronic controls were added. The new transmission was
coded F-31 and became known as the 4T60-E. The 4T60-E was
phased in from 1988 to 1990. You can tell by looking at
the bottom oil pan - it will be stamped with "4T60-E".
This transmission has much better reliability. By the
1991 model year, all FWD Overdrive transmissions were
the 4T60-E model.
As a side note, with the introduction of the
Northstar V-8s, a new low volume transmission was
developed for these applications. It is known as the
4T80-E. Very durable but very expensive, about 80%
higher in cost than the 4T60-E. Also 60 pounds
heavier.
With the introduction of the Supercharged 3800,
a few modifications to the 4T60-E were made. The
biggest change is the final drive unit, which is of
heavy duty design.The transmission still can't
handle the full torque of engines such as the SC 3800
and the DOHC 3.4L V-6s at redline during shifts. GM
utilizes Engine Torque Management to maintain
reliability. This consists of controlling engine rpm
and engine torque (through timing and fuel) during
shifts. That is why the SC 3800 and DOHC 3.4L do
not shift at redline at WOT.
For the 1997 model year, GM introduce the 4T65-E.
This transmission is a heavily reworked 4T60-E design
which includes such features as a 258mm torque converter
instead of 245mm, twin chains and special sprockets for
noise, Electronic Line Pressure (ELP) for ECM control
of pump pressure to better regulate shift quality,
revised fourth clutch, revised second clutch housing,
and many other improvements to reliability. The first
applications to receive the 4T65-E will be the
SC 3800 V-6 and the DOHC 3.4L V-6 to minimize the need
for torque management. The phase in will be three
years and will be complete by model year 1999.
The biggest cause of failure of the original
4T60 (440) is heat. [snip of restricted info] Through
control of shift points and torque converter lockup,
tranmission temperature can be controlled. There is
a temperature sensor in the transmission for the ECM
to monitor. This shows the STRONG recommendation
to add and external air/oil transmission cooler
for 4T60 (440) equipped vehicles.
#17
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OK......So........
In the end, your saying GM is poor, and screwed us all over by making a POS tranny that cant handle anything. I believe it. You hear about Ford'* engines blowing before there tranny'* go. Why would they do this? Wow, do they just WANT us to dislike them? I sware they ask for it
In the end, your saying GM is poor, and screwed us all over by making a POS tranny that cant handle anything. I believe it. You hear about Ford'* engines blowing before there tranny'* go. Why would they do this? Wow, do they just WANT us to dislike them? I sware they ask for it
#18
Senior Member
Certified Car Nut
The 4t-60e handled pretty much all the power the series I put out, the 4t-65 is worse in many regards. Personally i'd rather have a better engine then a better tranny.
#19
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True Car Nut
The 4t-60e handled pretty much all the power the series I put out