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Thread: shifting problem 4l60e

  1. #1
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    Default shifting problem 4l60e

    this is on a 99 c5 running 1 bar of boost.

    i had the 2-3 upshift set at 6200/124 kmh last year. i took the car out the second time this year and it wouldnt shift, i ran into the limiter set to 6400 and saw over 6600 rmp. i did two logs like that and quit (i didnt like the 6600 at all). i lowered the shift point to 5800/118kmh and the trans shifted. i raised it to 6100/118 and it shifted. the next day it wouldnt shift any more. im sick of running into the limiter, the belt jumps a rib.

    so, is the trans giving up the ghost or can that be some programming issue? (the first outing this year was just to check on the mixture, i made one pass to 5600, so i dont think it killed the trans.)

  2. #2
    Joe (Moderator) joecar's Avatar
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    Post tune file.

    Is tire/gear/speedo all correct...?

  3. #3
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    i did the transmission tuning two years ago and didnt touch anything since then except the 2-3 rpm. it always worked. in the meantime i lowered it to 6000/118 and it shifted. it almost looks like it shifts after a change and then quits shifting after a couple of passes.

    frankly, i forgot how to post files, i will try and remember.

  4. #4
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    so i managed to post the file. you will see some weird things in the trans tune, thats how iv had it set up for two years.

    so yesterday i set the 2-3 wot shift to 6100/118 and it shifted. today i made another pass and it shifted below 5900, 5929 being the highest rpm recorded.
    Attached Files Attached Files

  5. #5
    Joe (Moderator) joecar's Avatar
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    Are you saying it was shifting ok for 2 years and then now it suddenly does not shift after a few times...?

  6. #6
    Joe (Moderator) joecar's Avatar
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    Try this:
    - lower D0935-7 from 130 mph to 120 mph.
    - lower D0908 last cell (TP 100%) from 130 mph to 120 mph (same as D0935-7).
    - set D0920-2 to 133 mph (same as high cells in D0902).
    - set D0960-2 to 100% all cells.


    Your WOT 3->4 upshift MPH is close to 6000 rpm... try pulling it down to say 125 (do this in D0920-2 and D0902), and then creep up on 133 mph.


    Are you running a shift kit, if so, which one...?

  7. #7
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    exactly, trans did what i wanted for two years and quit shifting properly from 2-3 the first time i made a pass this year. no shift kit, everything stock. i will look into the stuff you mention. (i dont worry about the wot 3-4 shift, i have never done it and probably never will, unless i take the car to germany, but thats a long drive and another 100 km or so until the autobahn opens up. 120 kmh on the freeway here.)

    edit: i see the first 3 points concern the 3-4 shift. my values are the same as a stock tune. i never touched them. should i do all this to the 2-3 shift perhaps? d0960-2 are 100% in the stock tune indeed. the problem is my tp only goes up to 99.6%.

    what i will do is set all trans values to stock and see what happens.
    Last edited by dian; April 24th, 2017 at 04:40 AM.

  8. #8
    Joe (Moderator) joecar's Avatar
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    Ok, try the same concept on the 2->3 shift.

    Also try stock, like you said.

    Log these pids:
    SAE.VSS
    GM.ETCTP
    SAE.RPM
    SAE.ECT
    GM.TFT
    GM.TOS
    GM.TIS
    GM.TCCMODE
    GM.TCCSLIP
    GM.GEAR
    GM.TFMPRS
    GM.TRQENG
    GM.SHIFTLAST
    GM.SHIFTDELAY
    GM.TPSSHFT

  9. #9
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    so im back to this.

    while i had no problems tuning the engine (it still lives) i know nothing about transmissions or converters. my research has yielded the following (and please correct me if im wrong):

    - my transmission is very marginal behind 1000 nm of torque
    - the converter clutch is constantly slipping. thats hard to believe but seems to be the case
    - the max line pressure (if thats the correct expression) cant be increased with the software, its 90 psi.

    http://www.sonnax.com/tech_resources...-modifications

    so the clutch has been slipping for two years behind 1000 nm now and may very well be toast. i had relied on the "base tune" i got and because the part time shifts firmed up somewhat i was led to believe it was o.k. at wot also. not so apparently. so i took off the blower and decided to get a hold on the trans n/a first.

    here are two loggs, the first one (7) has tos and tis in it. i dont know what to make out of it. tcc slip is negative at wot. so either the input shaft speed is incorrect or my converter not only multiplies torque but the speed by some miracle as well. what am i missing? how can slipp cross zero during a wot pull?

    i understand "release" and "apply" are essentially the same, its the state of slipping clutch. why do they occur when d 1001 and d 1004 are set to max? how to get ridd of them and keep the converter off all the time? or at least during wot? 1002 is set to 80% throttle. the 1-2 shift happens under apply.

    i see a lot of inconsistencies in whats happening. I probably need a lot of education on this.
    Attached Files Attached Files
    Last edited by dian; June 8th, 2017 at 07:40 PM.

  10. #10
    Joe (Moderator) joecar's Avatar
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    I'll look at your files and report back.

    What is the color and smell of the fluid in the trans...?

    ~ posted by phone ~

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