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Thread: Silverado 4L80 swap no lock up

  1. #1
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    Silverado 4L80 swap no lock up

    Hello everyone. I have an issue with my truck not wanting to go into lock up. I've been working on this for about a week and have had limited success. I'll attach a log and my tune as well. Vehicle is a 2001 Silverado 1500 5.3/4L80 with stock converter that came with trans. P01/12202088OS So a couple of notes on what I've tried so far and the results:

    -HPTuners shows the PCM is commanding lock up and shows to going through the normal TCC modes

    -Could be just me but it seems more able to lock up when trans temps are on the cooler side (Normally runs 114 to 140 depending on outside temps)

    -I tried using a switch with a light to manually ground the TCC wire (Pin S) and when on the light illuminates so I know it is getting power but had limited results (Locked up once and held until I turned off the switch when I coming to a stop)

    -Converter is the original converter which came with the 4L80e. I was waiting to make sure that the trans runs good before ordering a Circle D 3200 with lock up

    -When manually commanding lock up in HPT with truck off, I can audibly here the TCC solenoid operating

    -Fluid levels are correct when warmed up

    -All gears work well and no code (other than the before mentioned p1870 Trans Component Slippage from converter still unlocked when PCM commands locked)

    I'm really leaning toward the converter clutches just being shot but if someone could look through the tune and data log and double check me I'd appreciate it. Thank you.
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  2. #2
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    increase your tcc duty cycle on the maximim to 99 and 90 on the minimum side,you could just have a worn bore in the valve body, mine was tossing the code for component slipping I replaced my valve body and now its good.

  3. #3
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    Quote Originally Posted by DougO View Post
    increase your tcc duty cycle on the maximim to 99 and 90 on the minimum side,you could just have a worn bore in the valve body, mine was tossing the code for component slipping I replaced my valve body and now its good.
    Thanks for the suggestion and I apologize for not seeing this until just now. I've tried changing that although it was 100 maximum and 90 minimum for what I did. I'm not sure if that could have an effect. I'm really leaning towards a worn bore in the VB as the transmission has 170k miles when pulled and I've almost covered all other possibilities.
    I was also wondering if my segment swap is not quite working properly but the truck seems to shift fine and operate correctly, minus the TCC.

    Also have a thread started here on performancetrucks.net
    https://www.performancetrucks.net/fo...-555318/page2/

  4. #4
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    I see you looking for lockup but it looks as though you're not even achieving 4th gear. Output shaft speed should be higher than input shaft speed but your log shows them the same in 4th.
    3rd gear is 1:1 ratio.

    Unless I'm missing something, and that's been known to happen.

  5. #5
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    Quote Originally Posted by 123pugsy View Post
    I see you looking for lockup but it looks as though you're not even achieving 4th gear. Output shaft speed should be higher than input shaft speed but your log shows them the same in 4th.
    3rd gear is 1:1 ratio.

    Unless I'm missing something, and that's been known to happen.
    So that’s something else that has been throwing me for a loop. I can feel the truck actually shifting into 4th gear but it doesn’t show on the shaft speeds like you’re mentioning. You can see at other points where I’m in 1st, 2nd and 3rd with the appropriate gear ratios showing in the shaft rpms. I dropped the pan yesterday and the fluid appeared to be clean. No a ton of clutch material

  6. #6
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    If it locks in 3rd, that would be your phantom shifting into 4th feeling.

  7. #7
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    Quote Originally Posted by 123pugsy View Post
    If it locks in 3rd, that would be your phantom shifting into 4th feeling.
    The log shows it is not commanding TCC lock up when it shifts into 4th gear. I was also under the impression that I may be feeling the converter lock and think it's 4th being applied but the logs are saying different.

    So you can see that when 4th gear is commanded the engine RPM drops as expected for the gear change but the ISS and OSS do not match as though it's in 4th (should be a .75)

    I'm getting an 1860 (Was orginally getting and 1870 code when started which is no longer coming up) code now and even when disabled or clearing DTC's it doesn't apply when commanded. The last part that leads me to believe a new VB is in order is that when I command the PWM Solenoid with the truck off, I can audibly hear it underneath the truck. It still doesn't apply when commanded in manual operations of the scanner. And last is I have tried wiring a manually grounded switch and that too yields no results.

    What I was hoping was a simple tune issue may be a mechanical issue of a worn I attached a picture of the log that I edited with paint to show shift points as well as the log this came from. I found another 12202088 OS 4L80 file and tried segment swapping with it (hence the name of log) and it produced the same results. Good shifting and normal operation; no tcc apply.
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    Last edited by BuckNasty92; 05-24-2019 at 12:38 PM.

  8. #8
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    Quote Originally Posted by DougO View Post
    increase your tcc duty cycle on the maximim to 99 and 90 on the minimum side,you could just have a worn bore in the valve body, mine was tossing the code for component slipping I replaced my valve body and now its good.
    Thank you for this, Doug!

    I ordered a remanufactured valvebody with a Sonnax TCC valve and redone bore and it fixed my problem as well. Trans is shifting and locking up great now and is so much better cruising on the highway.

    Oddly enough, after fixing my issue the before mentioned Output and Input shaft speeds are still not showing a difference corresponding to 4th gear. BUT the truck does shift into 4th as it should. No slipping that I can tell and the converter is only commanded to lock up in 4th gear. I'll post a log that shows this still.
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