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Think it my trans

Discussion in 'Drivetrain' started by Gregs, Jan 8, 2017.

  1. Gregs

    Gregs Member

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    So I have a 03 trailblazer, automatic transmission and when you drive forward it will go up to about 1500 rpms and drop back down to 1000 or so,and does so over and over again, it has no power and will only get up to about 10 or 15 mph. The engine runs great and at idle or if you're driving in reverse it does fine. It has no error codes and I'm totally stumped, any help would be much appreciated. Thanks oh and it just started doing this one day out of the blue.
     
  2. gmcman

    gmcman Well-Known Member

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    How many miles? Color of trans fluid?

    Will it engage gear when you select "D"

    Preliminary guess is you have a bad shift solenoid if the fluid checks out.

    Did the trans start slipping at all prior to this, any flares (rise in rpm) during shifts in the past?
     
  3. Gregs

    Gregs Member

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    It's got about 180k miles on it, Tran fluid looks fine, yeah it will engage gear, but it's like it doesn't have any power and the rpms bounce back and forth between 1000 and 1500 or so. And no it just really came out of nowhere.
     
  4. TollKeeper

    TollKeeper Well-Known Member

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    Sounds like his neutral safety switch to me. With the engine being rev limited.

    If you manually shift it to first, will it go above 1500 rpm?
     
  5. gmcman

    gmcman Well-Known Member

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    The fact you can only get up to 15 mph is concerning, how many times did you try to get it to move after you realized it had an issue? Hopefully you didn't smoke a clutch pack trying to drive it.

    Try starting from a stop in 2nd gear, if it will pull away under power then there may be hope.

    Note that when starting from a stop in 2nd, it will be in 2nd so it will feel sluggish until about 20-30 mph.

    When was the last time the trans filter was replaced?

    If you are mechanically inclined, then we can lower the trans pan and go from there. What's under the pan can seem intimidating but most repairs are not the difficult.
     
  6. TollKeeper

    TollKeeper Well-Known Member

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    Another test to see if it's the neutral safety switch, with the engine off, place into D drive, and then turn the key on. If it starts you have other problems like the neutral safety switch.
     
  7. Gregs

    Gregs Member

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  8. Gregs

    Gregs Member

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    Thanks for the suggestions guys... I'll do that and get back to you with the results. I can do engines all day but transmissions aren't my thing lol.
     
  9. TollKeeper

    TollKeeper Well-Known Member

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    The tells me it's not the trans. It's either being electronically rev limited by the computer, or by not getting enough fuel. I'm leaning to the first.
     
  10. Gregs

    Gregs Member

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    It does fine at idle... and in reverse. What can cause the Rev limiter to do that and more importantly how do I go about fixing it... also to repeat it's not throwing any trouble codes.
     
  11. TollKeeper

    TollKeeper Well-Known Member

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    Perform those tests above, see if the engine will start while the gear shift is in -D- drive, see if you can get above 1500 rpm while having the gear shift in 1st or 2nd gear. From there I won't be able to help much, I know the general principles of how it all works, but not how to go about fixing it.

    I have a v8 and you have the I6. The v8 don't have a rev limiter, at least mine doesn't.
     
  12. gmcman

    gmcman Well-Known Member

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    I'm pretty sure the rev limiter on the I6 is around 3K-3,500K in P or N. Pretty odd it only goes to 1500 though...that's a new one for me. Sounds almost like it's in REP ( reduced engine power) but why without any codes. Not saying Tollkeeper isn't correct about a lower rev limit when in gear but not sure why.
     
    Mounce likes this.
  13. gmcman

    gmcman Well-Known Member

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    Any updates?
     

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