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4L80E strange behavior..

Discussion in 'Chevy Trucks' started by caddy60, Feb 21, 2008.

  1. caddy60

    caddy60 Junior Member
    from Finland
    Messages: 2

    I´ve got 1995 6.5 turbo diesel GMC Suburban. 230000 driven. I´ve owned this wehicle for two months soon.
    Stange troubles appeared after driving few hundred miles. (Means I´ve driven few hundred miles with that now) Tranny does not work as it should. When driving ~50mph the tranny can´t decide which gear to use.. lock on and off.. And wehicle moves then really sticky, does not matter if it´s cold or warm. Revese sometimes does not react to accelerator pedal and sometimes it works fine. Is this kinda solenoid or sensor problem or what? :mad: There is only one trouble code, 36 (injection pulse width error(time long)). Does it relate to this problem? PMD/FSD is new and remote mounted. Fuel, oil and air filters are new and motor oil of course. Tranny oil is still the same, what there was, when I bought this Suburban. Oil level is allright.
    I had 1994 6.5 ext.cab before and it moved much slicky with no this kinda problems ever.
    Any ideas??

    My english is not so good, but try to understand me. :confused:

    I thank You beforehand!

    Juho From Finland
  2. caddy60

    caddy60 Junior Member
    from Finland
    Messages: 2

    Now I´ve changed trans oil and filter. Oil was really dark, but there wasn´t any metal or other material in oil pan.
    I noticed that accelerator pedal have sometimes problems with front gear too.. Engine ran only idle and does not react to acc.pedal. There was a little uphill and that is why truck does not moved forvard even with idle.
    This is not trans problem anymore.. There is still no other trouble codes with 36. :mad:
    Last edited: Feb 26, 2008
  3. snowcan

    snowcan Member
    Messages: 52

    Caddy, sounds like you have a failed injector pump if you have no other codes, have it checked by a professional because it is to expensive a part to guess at, takes about 4 hours to change if all goes well.
  4. welded wrenches

    welded wrenches Senior Member
    Messages: 177

    repair fix.get a large buper jack.jack up radiator cap about 7 feet and slide a 72 chevy 4by4 under it and then hmmmmm lol
  5. scottL

    scottL PlowSite.com Addict
    Messages: 1,600

    There doesn't have to be metal in the trans fluid and it still can be bad. If it's dark brown that's a good sign there's trouble. You probably don't know when the last time the fluid or filter were ever changed. I'd take that to a trans shop at this point.

    As for the accelerator pedal. If the truck is in park and you push on the pedal and nothing happens or it bogs down.... This would not be related to the trans. This then could be many other things probably a sensor. If you were talking about the truck doing nothing while in gear then your back to your trans or torque converter or probably both.

    It is a '95 with 230K miles ....
  6. Detroitdan

    Detroitdan PlowSite.com Addict
    Messages: 1,937

    ?? Why does it sound like injector pump? I'm not seeing that from the symptoms he described.

    I would say it's either the throttle position sensor or bad connection at the pmd. I remote mounted mine and had a bad wire cause a similar effect. It would idle fine, put it in gear and it would bog, rev up after a minute and puke black smoke, then drop back to idle regardless of pedal position.

    I went through 4l80e tranny trouble last year, but I don't know, yours sounds more engine related. ECM might be reading something wrong, in 95 they still had the trans controlled partly by a coalant temp sensor