EVERTHING NEED TO KNOW ABOUT A 4L60E/4L80E

Discussion in 'General Truck Forum' started by chevychase, Sep 8, 2013.

  1. chevychase

    chevychase Semi-Admin
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  2. chevychase

    chevychase Semi-Admin
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    GM 4L80E Reference Material and FAQ's. [HR][/HR]

    Housed in this thread is a compilation of resources that will help you to understand the GM 4L80 transmission better. You will find an numerical and alphabetical listing below outlining conditions, problems, parts, and names for the transmission.

    One of the largest concerns frequently mentioned is the dreaded harsh shifting and no up shifting into Overdrive. Remember the throttle position is considered the first base of troubleshooting after verifying the pass through connector is not leaking and pins look good. All wiring is connected, tight and you have good grounding everywhere.

    Harsh transmission shifts and no upshifts into Overdrive can be caused by a defective Throttle position sensor.
    This sensor helps determine engine load.
    Throttle position sensor low DTC 22

    P.S This is especially true with the earlier model vehicles era 1991-1992-1993

    Troubleshoot the sensor by verifying the voltage from the computer being 5.0 volts at PIN A. If you do not have close to 5 volts and within 4.8 to 5.2 volts then troubleshoot the delivering circuit. Pin A going back to the computer.
    Move the wiring and harness a bit while checking pin A.

    You will need to verify the throttle resistance within the throttle position sensor. If the resistance is intermittent or there is a bad connection then you can suffer shifting problems. Remember that a DTC will not always show up. The fault can still happen and not throw a DTC.


    Find the pin with resisted (feedback to the computer lead footed voltage[​IMG]
    Back probe the two wires and verify Pin C and B. One is ground and one is resisted voltage from the throttle. This is the business end of the Throttle position sensor.
    To find the pins:
    C should be ground. Set the multimeter on continuity and check for pin C and chassis ground. A beep will tell you that one of the wires came across is ground.
    Back probe the other resisted pin going back to the computer. Actuate the throttle a bit will let you know. Also the resisted pin has much less voltage.
    Actuate the throttle and you will see the resistance move in the multimeter. If it doesn’t then that pin supplies 5 volts. Leave it alone.
    1. The middle pin is the one you are after.
    2. Ground is what you are after.
    Record the Ohms between the two while the throttle is in idle.
    Once you locate and know the function of these three pins lets begin.
    Go to the middle pin the resisted voltage pin. Go to Pin C and with the ignition on and truck[​IMG] not started check the voltage with the throttle in idle.

    At idle you should get .47 to .5 volts from the middle pin or resisted pin.
    Actuate the throttle slowly. There should be a dedicated and dependable[​IMG] rise in voltage. On some there is one break while actuating to full throttle. When you get to full throttle there should be <<<<4.7>>>> to <<<4.8>>> volts registering through the resisted pin.

    Verify through Ohms the same test. You should see resistance move as well.
    If the graduated range is not smooth then get another TPS.
    Clear the codes by disconnecting the batteries. Reconnect and drive the vehicle[​IMG].

    P.S. Remember this pin tells the computer where your foot is on the fuel pedal.
    It helps determine engine load. The Engine RPM (ESS) Sensor helps out as well.


    1


    2 - Second Gear only condition - See VSS below or this thead


    3


    4



    A


    B


    C If you want to build your own Stand Alone Transmission controller there is a link for you. MegaShift - (c) 2004, 2012 Bowling and Grippo


    D


    E

    Electrical component diagnosis information - see this attachment This helps to spell out better the solenoid's roles and electrical/sensor responsiblities in the system.

    F


    G Gear Ratio Errors DTC 85, 86, 87. Quote:
    [TABLE]
    [TR]
    [TD="class: alt2"] Gear ratio error codes. DTC 85,86, 87.
    The input speed sensor and the output speed sensor/vehicle speed sensor determine these ratios. The transmission range pressure switch tells the computer what gear you commanded (selected). 1st, 2nd, 3rd, 4th ect. The speed sensors tell the computer the input gear speed and the output gear speed. If it doesn’t jive with the logic then the computer thinks there is something wrong. The Transmission range pressure switch is feedback to the computer for what gear you selected.

    Causing the ratio error codes.
    It could be the speed sensors/ Transmission Range pressure switch/ hanging valve for a DTC 87 for instance. It could be bad/intermittant grounding or a connection. The speed sensors develop their own electrical current.
    It could be worse than electrical and could be hydraulic/ mechanical. If the commanded gear is 4th and the transmission cannot get to fourth for instance. The computer expects to be in fourth. Clutches are pressure held by a piston. If the piston doesn’t work or leaking and the clutch doesn’t put the transmission in the gear you selected then you can’t command it right?
    DTC 85 Undefined Gear Ratio will set when unknown gear ratio is detected for any gear but 4th.

    DTC 86 Low Gear Ratio This DTC will set when transmission commanded gear is 1 or 2 and transmission is mechanically in 3rd or 4th gear.

    DTC 87 High Ratio Error: This DTC will set when transmission’s commanded gear is 3 or 4 and transmission is mechanically in 1st or 2nd gear.

    Speed sensors work by putting out voltage whether low voltage or high voltage. The voltage is based by gear RPM. The gear that the speed sensor takes its reading off of is called a reluctor. If the reluctor is unserviceable, if the speed sensor is unserviceable, Wiring connection is not twisted/ bad connection/resisted/intermittant connection. You are going to get one or more of these codes.
    The computer is programmed to think PROBLEM SO PROTECT. [/TD]
    [/TR]
    [/TABLE]


    H


    I


    J


    K


    L

    Line pressure - Transmission line pressure - check this post for the internal operating conditions.

    Low voltage at Pin E? Verify voltage like this poster ran into. 4L80E Electrical ? 2nd gear only :( Post #22.
    M


    N


    O


    P Passthrough connector. The pins and where they go.
    http://www.dieselplace.com/forum/sho...51#post3823951


    Q


    R Binding in Reverse

    I have not noticed that problem, and I've accidentally missed R going from D and stopped in N and revved it, and it didn't lurch like it was in gear. I'll check next time I drive it and make sure N is still N!

    Is there something specific that causes N to be a drive gear?
    Thanks,
    Don.


    Quote:
    [TABLE]
    [TR]
    [TD="class: alt2"] Usually when I experience a bind up in reverse, it is because the forward clutches failed. The forward clutch is on in all forward gears only. When the forward clutches fail they go metal to metal and what you have is too much clearance in the drum causing the forward apply piston to come out of its bore. When this happens, the forward apply piston will not return to the release position and the clutches stay applied no matter what gear you put it in including reverse or neutral. MikeL [/TD]
    [/TR]
    [/TABLE]



    S

    Sensor and Solenoid resistance table - See this post.

    Solenoid Locations Picture - found in this attachment

    Solenoid schematics/wiring - See this attachment

    Shop inspection: http://www.dieselplace.com/forum/sho...15#post3805515

    T Torque converter shudder: http://www.dieselplace.com/forum/sho...34#post3627834

    TCC - Torque Converter Clutch - the clutch that locks the tranny instead of passing engine torque through the torque converter. This reduces heat in the transmission and improves fuel economy similiar to a manual transmission.


    TISS - Transmission input speed sensor

    Torque Converter Clutch (TCC) - not engaging? See this thread for details.

    TOSS - Transmission output speed sensor




    U


    V

    VSS - Vehicle speed Sensor See this thread


    W TCM wiring diagrams can be found HERE


    X


    Y


    Z
     
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  3. chevychase

    chevychase Semi-Admin
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    Why your transmission can shift hard. High line pressure.
    These codes are for vehicles designed for the older vehicles. One designed for the later model vehicles will follow.

    This is an Electrical breakdown for electrical problems associated with high line pressure problems. Further down is a short and skinny on the mechanical breakdown for high line pressure.
    Actually there are several reasons why high line pressure happens. One type is by design whether the computer or transmission. The computer has default settings to protect the transmission. The transmission has a couple as well.

    Causes for high line pressure.

    Loose PCM connections. Very overlooked. When troubleshooting its going to take time. Look and check pin to pin from the PCM to the transmission, VSS, TOSS, TISS.

    Connectivity through the pass through connector at the transmission connector.
    All grounding concerning the PCM, Transmission, Battery, Terminals at the battery, Battery to chassis ground, Engine block to chassis ground. All grounds.
    Positive terminal not serviced.


    DTC 21 High voltage. The computer is receiving high voltage.

    DTC24 Vehicle speed sensor (VSS) or Transmission output speed sensor (Toss) low.

    DTC52 High voltage ie excessive voltage.

    DTC 72 TOSS Transmission output speed sensor.

    DTC 73 PCS Circuit or force motor. >0.16 amp from command amperage that lasts longer than one second. This is the solenoid that the computer controls for line pressure. If there is a problem with this circuit such as amperage or voltage drop the computer protects the transmission by maximizing line pressure as by design.

    DTC 75 system voltage low.

    DTC 81 2-3 shifting circuit. Solenoid on and stays high or solenoid off and stays low.

    DTC 82 1-2 shifting circuit. Solenoid on and stays high or solenoid off and stays low.

    DTC 85 undefined gear ratio defaults into second and maximum line pressure.

    DTC 86 low ratio error.

    DTC 87 high ratio error.




    Mechanical/hydraulic Not electrical

    Oil pump problem. Transmission pump.
    Seals within the transmission
    Damaged gearing.
    Transmission pump bushing worn, scored.
    Pressure regulator valve, spring.
    Reverse boost valve
    Pressure relief valve collapsed or broken.
    Pressure control[​IMG] solenoid stuck off or on.

    TCM fault.

    A list of diagnostic trouble codes found on the web.


    OBD-II Check Engine Light Trouble Codes
    A Basic chart to follow. Not an answer to all but a guide.

    [TABLE="class: ncode_imageresizer_warning"]
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    [TD="class: td2"]This image has been resized. Click this bar to view the full image.[/TD]
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    [​IMG]Digsby
    IM, Email, and Social Networks in one easy to use application!
    Digsby = IM + Email + Social Networks





    [TABLE="class: ncode_imageresizer_warning2"]
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    [TD="class: td2, width: 100%, align: right"]A chronic problem with higher mileage Gm type transmissions. Especially the 4L80-E. The Torque converter clutch solenoid is a pulse width solenoid and opens on command by the computer through pulsing. wear is created at the sleeve as seen below. The seal can wear as well, this picture doesn't illustrate a good example of a TCC solenoid actuator valve seal. Changing fluid frequently is a must for preventative maintenance. Follow user manual. I recommend 30,000 mile intervals. Debris can accelerate wear.

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    [TD="class: td1, width: 20"][​IMG][/TD]
    [TD="class: td2"]This image has been resized. Click this bar to view the full image.[/TD]
    [/TR]
    [/TABLE]
    [​IMG]

    A hydraulic diagram of the Torque converter solenoid and how it interacts with the Transmission pump. Lockup happens when the Torque converter clutch is hydraulically pressured to the right.

    [TABLE="class: ncode_imageresizer_warning"]
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    [TD="class: td1, width: 20"][​IMG][/TD]
    [TD="class: td2"]This image has been resized. Click this bar to view the full image.[/TD]
    [/TR]
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    [​IMG][/TD]
    [TD="class: td1"]Report this image[/TD]
    [/TR]
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  4. 96silverado

    96silverado Full Member

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    Wowzerz,what a plentyful Transmission info Jackpot ! !
    Thanks so much you!
     
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  5. BurbanMan

    BurbanMan Full Member

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  6. 96silverado

    96silverado Full Member

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    Just wanted to add this pick taken from Burbanman's other post because it should also be here too!

    500x347x500px-4L60EValveBodyExView1.jpg
     
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  7. chevychase

    chevychase Semi-Admin
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  8. chevychase

    chevychase Semi-Admin
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  9. chevychase

    chevychase Semi-Admin
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    HAVE YOU TRIED THE NON-SCAN TOOL METHOD .

    NOTE: If the Crankshaft Variation Relearn is not accessible through your scan tool (some truck applications 1998 & later), perform the relearn in the following manner:

    1. Turn off all of the accessories. With the Air temperature sensor and Coolant temperature within 5 degrees (Centigrade) of each other, start the engine and let it idle in Park or Neutral for two minutes.
    2. Accelerate the vehicle to 55 mph at part throttle. Cruise at 55 mph for 8- 10 minutes until the engine reaches operating temperature.
    3. Cruise at 55 mph for another 5-6 minutes.
    4. Decelerate to 45 mph without using the brakes, and maintain 45 mph for 1 minute.
    5. Perform 4 deceleration cycles, without using the brakes, of 25 seconds each where no specific speed is necessary. Returning to 45 mph for 15 seconds in between deceleration cycles.
    6. Accelerate to 55 mph and cruise for 2 minutes.
    7. Stop the vehicle and idle for 2 minutes with the brake applied and the transmission in Drive (automatic trans.) or Neutral (manual trans.) with the clutch depressed.
     
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  10. chevychase

    chevychase Semi-Admin
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    Found this to add
    t is fairly simple to make a 4L60E harness from a 1/2 ton 5.3L truck work with a 4L80E transmission. These same steps will work for an 99-07 Vortec Truck, LS1 99-02 style harness, or 04 GTO harness for that matter (some wire colors maybe different on GTO) Remember 99-02 PCM's used BLUE and RED pcm connectors, 2003+ use BLUE and GREEN PCM connectors. The wire locations are the same for all years, so this process is the same no matter what year your truck harness is.
    There will be a few changes to the pins at the transmission plug, and at the PCM plugs.
    The first step will be to remove the cover over bottom of the pins on the 4L60E transmission plug. There is a small plastic tab holding each pin in place, this tab must be lifted, then push the pin over, and out the back of the connector. (Same process at the PCM.)
    [​IMG]
    You will need to REMOVE 2 wires, and MOVE 1. Each wire has a label in the rubber insulation. The middle row shown, L,M,N,P,R,S. Q and O are not used. T, U is the bottom row.
    In the picture below, we REMOVE
    the WHITE wire, in location S,
    the TAN/BLACK wire, in location T
    [​IMG]
    The next step, will be to MOVE the BROWN wire, in location U, to location S where there was previously a wire. You should use some silicone to fill in the now empty T and U cavity's.
    [​IMG]

    That is all that needs done to the round gray transmission plug. It is now ready to plug into the 4L80E transmission.
    The 4L80E transmission has two speed sensors, 4L60E only used one. You will now have two extra wires, these will be used for the 4L80E's INPUT speed sensor. Attach a speed sensor pigtail to the WHITE and TAN/BLACK wires removed a few steps above. It does not matter where these two wires go in the two pin speed sensor plug. Polarity does not matter. The existing speed sensor wires from the 4L60E (purple/white and green/black wires twisted together) will hook to the speed sensor directly above the round gray trans connector on 2wd's, or in transfer case adaptor, or transfer case output housing on 4x4 applications. The new speed sensor plug will hook to the INPUT speed sensor, located abover the shifter shaft on the side of the 4L80E.
    That will complete the wiring changes at the transmission end. Now, you will need to go to the PCM connectors, and re-purpose the WHITE and TAN/BLACK wires for the input speed sensor.
    The WHITE wire will be found at the C1 (BLUE) Connector PIN #79. Remove this pin, and MOVE it to C2 (RED or GREEN) Connector PIN #22.
    The TAN/WHITE wire will be found at the C2 (RED or GREEN) Connector PIN #42. Remove this pin, and MOVE it to the C2 (RED or GREEN) Connector PIN #23.
    The PCM programming must match for a 4L80E as well.
     
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