P0740 tranny code

Discussion in 'KJ General Discussion' started by HoosierJeeper, Jan 6, 2016.

  1. HoosierJeeper

    HoosierJeeper Gold Supporter/Admin Staff Member Administrator

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    Got a P0700 yesterday, took it to the local shop and they got the P0740, TCC circuit error. Any ideas? Drives just fine and the light went out on its own.
     
  2. dude1116

    dude1116 Full Access Member

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    More than likely the beginnings of a failing solenoid pack (most common issue with these transmissions). If the TC is locking normally, then you are still OK to keep driving it. My solenoid is on its way out and my TC rumbles and shakes at lockup.
     
  3. HoosierJeeper

    HoosierJeeper Gold Supporter/Admin Staff Member Administrator

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    How hard is it to fix? Has yours been on its way out for a bit?
     
    Last edited: Jan 6, 2016
  4. dude1116

    dude1116 Full Access Member

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    Mine has slowly been on it's way out since shortly after I put this used trans in. (almost 80k miles, 3 years-ish?)

    It's been very bad since shortly before lifting. (15k miles)

    Fixing the solenoid requires a full transmission break down and rebuild, unfortunately.

    My understanding of how the internals of the tranny work is like this: The solenoid is on the valve body and tells the valve body when to open and close to let fluid through to the TC. When the solenoid fails, the valve body will open and close more or less randomly until the TC fails for one reason or the other.

    Someone please correct me if I'm wrong.
     
  5. HoosierJeeper

    HoosierJeeper Gold Supporter/Admin Staff Member Administrator

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    Last edited: Jan 6, 2016
  6. HoosierJeeper

    HoosierJeeper Gold Supporter/Admin Staff Member Administrator

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    Is there anything preventative that I can do? I get the fluid flushed about every 40k by the dealer. It has new fluid in it now. Or is it just a matter of waiting till it starts acting up?
     
  7. uss2defiant

    uss2defiant Full Access Member

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    curious, are you experiencing any hard shifts?
     
  8. HoosierJeeper

    HoosierJeeper Gold Supporter/Admin Staff Member Administrator

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    Nope. Shifts pretty good. Wouldn't say it shifts like a Bentley but it shifts as good as it ever has.
    Also, is there any possibility that it could be an issue within the wiring harness from the PCM/TCM?
     
  9. JeepJeepster

    JeepJeepster Full Access Member

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    Hmm yeah you can easily replace the valve body or the solenoids without a major overhaul. If you wait till the TC self destructs then it would need an overhaul...

    I wasnt aware the solenoids were common to go bad in the 42rle. I knew they were in the 42re/44re/46re...
     
  10. HoosierJeeper

    HoosierJeeper Gold Supporter/Admin Staff Member Administrator

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    Would the symptoms dude1116 is experiencing be indicative of the TC self destructing? Or at that point could you still replace the solenoids/ valve body and be ok?
    I guess my question is, is it safe to wait to see if it comes back or shows symptoms?
     
    Last edited: Jan 6, 2016
  11. eyehatetofu

    eyehatetofu JPOTM WINNER

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    I had that and a p700 code a year ago. Kept driving it and eventually the torque converter went kaput. Kept driving it then started having hard shift problems. Kept driving it then the trans would overheat. Now am looking for a replacement trans and TC. I would suggest not driving it as it continually gets worse; didn't work out well for me. :D
     
  12. dude1116

    dude1116 Full Access Member

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    A good family friend is a trans shop owner and sees these things in all the time for this issue.

    As far as replacing the valve body and solenoids without overhaul...you can. But the labor is ridiculous and you might as well have all of the "soft" parts of the trans rebuilt at that.

    My TC is definitely self destructing. I'm already considering my whole trans toast. Some argue that you can replace just the TC and the valve body...but at that I've probably had pieces of TC clutch go all through the trans. So the idea is to run this one into the ground and throw another used trans in. This Jeep has 155k miles. I don't need extreme longevity out of another trans.

    Between two junk yard trans's (installed), I will have paid the same amount for a rebuilt one (installed).
     
  13. HoosierJeeper

    HoosierJeeper Gold Supporter/Admin Staff Member Administrator

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    Is the labor that bad on the valvebody? I looked a few how to's and it seems like, as long as you're swapping in a new one and not rebuilding it, it's not too bad.
     
  14. HoosierJeeper

    HoosierJeeper Gold Supporter/Admin Staff Member Administrator

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    Would replacing the solenoid pack be a viable option if I'm not experiencing drive ability issues yet? I see the pack listed in parts catalogs.
     
  15. dude1116

    dude1116 Full Access Member

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    Anything's possible if you want to try it. :shrug: From what I see it looks easy-ish too. Maybe the labor charged includes removing the trans?
     
  16. JeepJeepster

    JeepJeepster Full Access Member

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    Yeah its no problem to drop down a valve body. More so if youre just replacing it with a new one.

    Personally I wont be happy if I don't get at least 200,000 out of my factory 42rle transmission. I've got 227,000 on my ZJ's 42re and Ill be upset if it doesn't see 300,000.
     
  17. HoosierJeeper

    HoosierJeeper Gold Supporter/Admin Staff Member Administrator

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    It seems like the way these things progress would be the codes indicate a solenoid acted up (how often, idk since some seem to work fine anyway) then solenoid(s) start acting up all the time then that damages the rest of the tranny. So if you catch it early enough before they bad solenoids ruin the tranny by acting up you should be ok.

    The only part of doing it myself I'm not sure about is the relearn. Looks like doing the key thing off-on 3 times won't work. Lol.
     
  18. mightybeet

    mightybeet Full Access Member

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    id suggest replacing both valvebody and solenoids if ya can afford. if the solenoid is acting up id say its cause yer valves are losing pressure from internal wear... which im still dealing with cause im lazy and dont feel like changing the valvebody till it gets warm again.......

    there is a quick and dirty relearn on here somewhere where ya remove the wires from the battery, hook them together(not on the battery), turn the key to ON and press/hold the brake pedal for 10 minutes. thatll hold ya off to find a good transmission place that has a scanner to do the relearn.
     
  19. dude1116

    dude1116 Full Access Member

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    Pretty sure that's a myth.
     
  20. mightybeet

    mightybeet Full Access Member

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    which? the quick and dirty or finding a good transmission place?