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DrStrangeLovII

@12.189.32.x

GM 4T60-E Transmission

GM 4T60-E Transmission

On this transmission, it has Seven Wires

A. Two wires for temp sensor
B. 1-2 shift wire
C. 2-3 shift wire
D. TCC wire
E. TCC PWM wire
F. Ground Wire

Anyway to manually hook up this transmission? Just a manual "shift box," not integrated with engine sensors.

There is a company that offers ($700.00) a stand alone computer solution: »www.powertraincontrolsolutions.c···t-4.html

Here's some details on GM THM-4T65E (newer transmission) that may give a sense of what's happening:

This transaxle is a fully automatic and electronically controlled. Shifts are all controlled by the pcm by two shift solenoids, line pressure is also fully electronic and controlled by a Pressure Control Solenoid, or EPC which is commanded by the pcm. This transaxle also employs the use of a Torque Converter Clutch, or TCC and is used to further enhance gas mileage and keep engine rpms lower. The TCC style in this trans is a PWM type, which stands for Pulse Width Modulation. This style PWM TCC system was developed to allow for a smooth engagement of lockup and allows constant slippage of the TCC and can apply in 2nd through 4th gears. The constant slippage is tolerable to the converter because of a special TCC lining developed especially for this purpose and is called a Woven lining. An ordinary TCC clutch would burn up and shudder vilently if used in this type of system.
»www.tripleedgeperformance.com/4T···Info.php


mattmag
Premium,ExMod 2000-03
join:2000-04-09
NW Illinois
kudos:3

1 edit


You could probably fashion a manual-shift box, but the TCC would not be pulse-controlled any longer, of course. I don't really think the setup would be very good, but it should be possible. Most of the computer-controlled circuits are switching ground lines, so it would have to mimic the factory setup exactly to work.

EDIT: Thinking more about this, it will be very problematic. Some of the shift sequences involve disengaging one shift solenoid while activating the other, so making two "electrical box" switch changes at once could be a challenge...


IllIlIlllIll
EliteData
Premium
join:2003-07-06
Hampton Bays, NY
kudos:7
its possible.
i did it on my 1996 chevy astro.
i installed a few switches to test the theory out.
(i have since reconnected the control to the PCM after the test)
4 switches to switch each gear and one for lockup.
of course, the control from the PCM would have to be disconnected for this to work properly.
the lockup switch is one idea i havent disconnected.
i like the idea of the TC in full lockup at 40MPH or faster and not disengaging when you release the thottle for a second (most vehicles do this).


DrStrangeLovII

@12.189.32.x
reply to mattmag
said by mattmag:

EDIT: Thinking more about this, it will be very problematic. Some of the shift sequences involve disengaging one shift solenoid while activating the other, so making two "electrical box" switch changes at once could be a challenge...
On last URL cited above, this person has a "Shift Solenoid Patterns for each gear," for that transmission.

What I would need to understand is the PWM TCC system, in terms of the Pulse Width Modulation...this "system" would not be a big deal to duplicate...but knowing how/why is what is needed.

A manual shift box could be made, with minor "computer circuit."

All that $700 controller does, is take the various inputs (throttle, etc) so that all goes smoothly....but with a manual shift box, you can control the acceleration and let this be the pattern for shifting.

I'm really looking for tech info here...or a company that makes a cheaper version.


DrStrangeLovII

@12.189.32.x
reply to IllIlIlllIll
said by IllIlIlllIll:

i like the idea of the TC in full lockup at 40MPH or faster
TC Full Lockup was the norm in early transmissions around 1980 era...but with latest transmissions, they have a "constant slippage" mode.

GM went from 4 wire plug, to 7 wire, then 7+ wires (I think) on 4T65E.

And with Full Lockup transmissions, they played with how TC was engaged/disengaged. Now, they have this "constant slippage" mode, which works with this "PWM TCC system."

Hence, on newer stuff, one needs to get a foothold on this PWM TCC system before making a manual shift-box.


mattmag
Premium,ExMod 2000-03
join:2000-04-09
NW Illinois
kudos:3


You will be missing far too many data inputs to make Pulse-Width Modulation a reality by just using the shift pattern. It is far more than just a program or routine. It needs to know throttle position, manifold absolute pressure, barometric pressure, coolant temperature, fuel flow rate, airflow rate, transmission gear position and ambient temperature just to name the few I can think of off the top of my head.

Sounds interesting...but VERY complex!


IllIlIlllIll
EliteData
Premium
join:2003-07-06
Hampton Bays, NY
kudos:7

1 edit
true.
even if you were to do this manually (without any input from any sensor, even with a computer module) you would have to know when to downshift at certain speeds such as going uphill, when to upshift and when to release back to the appropriate gear depending on the speed.
most of the data taken for gear shifting is done by the speed sensor and TPS sensor, and on some vehicles, the engine rpm.
so while my test did work, it was the biggest pain in the ass to drive that way, lol.


DrStrangeLovII

@12.189.32.x
reply to mattmag
said by mattmag:

You will be missing far too many data inputs to make Pulse-Width Modulation a reality by just using the shift pattern.
Sounds interesting...but VERY complex!
I might add, the driver would have to maintain the same pattern to make it work...in other words, slow and steady.

Yes, if you wanted the driver to drive it like people normally do, you would have to fall back to a computer making the decisions.

In analogous terms, I drive a 18 wheeler that has a gauge that shows engine boost pressure...I normally don't exceed 10 pounds of boost...but on hills, I go upto 25+ pounds of boost...hence, if your foot in "trained," it could be done, but you would have to stay within those parameters required, always, which most people would not.

Oh well, I thought there might be a simple back door...


sdgthy

@optonline.net
reply to mattmag
None of the factory controllers care about ambient temperature, and those that use MAP only guesstimate barometric at startup and WOT. Coolant temp is minor, that's only used to prevent TCC lockup until the engine warmed up.

There's only 3 things that absolutely need to be known, load, throttle position and speed. Factory controllers do also look at other things, such as EGR.


mattmag
Premium,ExMod 2000-03
join:2000-04-09
NW Illinois
kudos:3
said by sdgthy :

None of the factory controllers care about ambient temperature, and those that use MAP only guesstimate barometric at startup and WOT. Coolant temp is minor, that's only used to prevent TCC lockup until the engine warmed up.

There's only 3 things that absolutely need to be known, load, throttle position and speed. Factory controllers do also look at other things, such as EGR.
You're way off on that one.

Nearly all newer GM products look at ambient during cold weather and when below a specific value (generally in the 40 degree range) they delay the normal shift sequence and provide a higher RPM shift point. This is done to provide a small reduction in engine coolant warm-up time, which has obvious benefits.

How do you suppose the factory controller determine load? It's a computation between MAP, TPS, and MPH. It's much more than a "guesstimate" at start-up...


Turftech
Flying on empty
Premium
join:2002-01-03
Up the River
reply to DrStrangeLovII
Reflecting Matt's comments, are you trying to say that all these components have been added redundantly or superfluously? Take a peek at how long and how tricky it was to make the new VW/Audi/etc. "manual" control automatics. They are as close as we have come to what the OP is looking to achieve. They rely on a plethora of sensors. IMHO, not worth it. You would end up with some goat of a vehicle.

(I will edit in the name of the transmissions I refer to)
--
Serving doughnuts on another planet.


sdgthy

@optonline.net
reply to mattmag
And how do you propose they do that without a barometric sensor? GM did away with a baro sensor when they switched from differential sensors to MAP. Try reading a PCM hack, or better yet hack one yourself to really understand what it's doing.

And yes, some sensors are redundant. The PCM can calculate load from just one, if others have failed. And most are just fluff or added for OBD2 purposes, which is not to make the engine control any better. OBD2 was mandated by the EPA to monitor the emissions controls.


mattmag
Premium,ExMod 2000-03
join:2000-04-09
NW Illinois
kudos:3

No,the PCM can not "calculate" load from just one input; it extrapolates it, which is a significant difference. It is not an accurate reading, it is an estimate to be used as a fall-back value in the case of a component failure.

Whether you want to believe it or not, the current crop of sensors with digital data capability has led to improvements in many facets of a modern automobile.


McSummation
Mmmm, Zeebas Are Tastee.
Premium,MVM
join:2003-08-13
Fort Worth, TX
kudos:2
How is the "load" determined when all the sensors are working?

The 4L80E in my '96 K2500 pickup has a "torque sensor" in it. Is this related?


mattmag
Premium,ExMod 2000-03
join:2000-04-09
NW Illinois
kudos:3


There is no "torque sensor" in a 4L80E. Did you see that notation somewhere? There is a torque converter clutch solenoid, similar to what we were discussing above. Nothing that senses torque in the trans itself though.


McSummation
Mmmm, Zeebas Are Tastee.
Premium,MVM
join:2003-08-13
Fort Worth, TX
kudos:2
Sometime between when I read the diagrams for my 4L80E and now, I confused "force motor" with "torque sensor".

I think I'll go back to my nap now.


mattmag
Premium,ExMod 2000-03
join:2000-04-09
NW Illinois
kudos:3


Ahh, OK. Force motor, aka "Pressure Control Solenoid". That's the modern-day electronic version of a throttle valve, or vacuum modulator. It responds by changing the valve body line pressure in correlation to throttle position and engine load.


McSummation
Mmmm, Zeebas Are Tastee.
Premium,MVM
join:2003-08-13
Fort Worth, TX
kudos:2
Or, as one thing I read said, "based on the torque generated by the engine".


sdgthy

@optonline.net
reply to McSummation
Primarily manifold pressure, throttle position and rpm. There's a few others that have a minor effect, such as coolant temp and A/C request.