OP
OP
Preparing to replace 4L60e myself.
- Thread starter Merc1973
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Tonyrodz
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Ive got 50 tunes on this laptop that says you, google boy, and your cheerleader above dont have a clue. But nah, you know it all.
.....now boys.
I was talking to a well known local tuner, and understand ive tuned plenty of cars, but I wanted to ask him since he did it for a living and may have seen something I hadnt. I specifically talked about the shift time error data. He stated to me that yes he has logged this data live while tuning a car on the road, and he never saw any change in it (meaning the computer isnt modifying shifts). From the factory the commanded "theoretically asked for" shift time is set around .250. So its asking for the shift to take place in 1/4 of a second. The way we know it isnt adaptive is because if you logged error and the shift was an actual .400 youd get an error of .150 correct? Now if you change shift time to .000 you now get an error of .400. It simply may not be able to shift any faster. It can change line pressure through force motor current but again there is a max value that it cannot exceed regardless of conditions and the force motor and pressure modifier tables are set for engine torque output and/or trans temp. Also, the pressure tables are set to get firmer as engine torque increases, giving you a progressively firmer shift as you get more aggressive with the throttle, but that's still not adaptive in a learning changing sense.
swampfoxjr
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Their website is nonexistent which is strange.
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humblebeast07
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Just had to make the same decision on my 03 Yukon 4x4 with 146k, 3-4 clutches where toasted a few months ago....to buy rebuilt and self install or get someone to rebuild mine.... I wanted a performance build, long story short I ended up getting a local guy to rebuild with a rebuilt converter, corvette servo, transgo shift kit, beast sunshell, red alto 3-4 clutches, some machining on the valve body, and complete rebuild other wise...install and all for 1700....my biggest thing is I wanted it to last at least another 150k, or eol of the vehicle lol
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Tonyrodz
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That's a damn good price with all those goodies.
humblebeast07
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Ya, I first hit him up on the cost of just a bench rebuild, and he told me 1400 but he prefers to do the install to remove the chances of installer errors....he told me all he asks for it to make it worth his time, so he quoted me 1700 otd and next question was when can I drop it off.....Im in Houston, TX though and with all the trucks and hot rodders/street racers there is alot of competition in the transmission market, keeping prices competitive.
Our local known builder charges 1050 for that build.
Tonyrodz
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Really? Guys around here are super expensive! That's like $2000 or more around here.
humblebeast07
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With a warranty??, I could have got it close to that but from a home shop...but 1yr 12k mile warranty from a 30yr old established shop?
Tonyrodz
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From a place like Aamco, professional place, with a warranty.
humblebeast07
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i mean for 1050
swampfoxjr
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I definitely went to their shop & picked my transmission up
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OP
OP
Merc1973
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Thank you, factual post without ad-hominem comments. Thanks for the data. You're correct the shift times do not change but I do feel the line pressure changes (adaptations) like I stated previously. I may not have been as specific about what changed.
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OP
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Merc1973
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Transmission Adaptive Functions
(Source: AllData)
The 4L60-E transmission utilizes a line pressure control system during upshifts to compensate for the normal wear of transmission components. By adjusting the line pressure, the PCM can maintain acceptable transmission shift times. This process is known as "adaptive learning" or "shift adapts" and is similar to the closed loop fuel control system used for the engine.
In order for the powertrain control module (PCM) to perform a "shift adapt," it must first identify if an upshift is acceptable to analyze. For example, upshifts that occur during cycling of the A/Ccompressor or under extreme throttle changes could cause the PCM to incorrectly adjust line pressure. When an upshift is initiated, a number of contingencies, such as throttle position,transmission temperature, and vehicle speed, are checked in order to determine if the actual shift time is valid to compare to a calibrated desired shift time. If all the contingencies are met during the entire shift, then the shift is considered valid and the adapt function may be utilized if necessary.
Once an adaptable shift is identified, the PCM compares the actual shift time to the desired shift time and calculates the difference between them. This difference is known as the shift error. The actual shift time is determined from the time that the PCM commands the shift to the start of the engine RPM drop initiated by the shift. If the actual shift time is longer than the calibrated desired shift time, a soft feel or slow engagement, then the PCM decreases current to the pressure control (PC) solenoid in order to increase line pressure for the next, same, upshift under identical conditions. If the actual shift time is shorter than the calibrated desired shift time, a firm engagement, then the PCM increases current to the PC solenoid in order to decrease line pressure for the next, same, upshift under identical conditions.
The purpose of the adapt function is to automatically compensate the shift quality for the various vehicle shift control systems. It is a continuous process that will help to maintain optimal shift quality throughout the life of the vehicle.
Clearing Transmission Adaptive Pressure (TAP)
Transmission adaptive pressure (TAP) information is displayed and may be reset using a scan tool.
The adapt function is a feature of the PCM that either adds or subtracts line pressure from a calibrated base line pressure in order to compensate for normal transmission wear. The TAP information is divided into 13 units, called cells. The cells are numbered 4 through 14. Each cell represents a given torque range. TAP cell 4 is the lowest adaptable torque range and TAP cell 14 is the highest adaptable torque range. It is normal for TAP cell values to display zero or negative numbers. This indicates that the PCM has adjusted line pressure at or below the calibrated base line pressure.
Updating TAP information is a learning function of the PCM designed to maintain acceptable shift times.
It is not recommended that TAP information be reset unless one of the following repairs has been made:
- Transmission overhaul or replacement
- Repair or replacement of an apply or release component, clutch, band, piston, servo
- Repair or replacement of a component or assembly which directly affects line pressure
Resetting the TAP values using a scan tool will erase all learned values in all cells. As a result, the PCM will need to relearn TAP values. Transmission performance may be affected as new TAPs are learned. Learning can only take place when the PCM has determined that an acceptable shift has occurred. The PCM must also relearn TAP values if it is replaced.
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