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  1. #1
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    Tmaxx 2.5 trans wont shift!! Please help!!!

    Have a T-MAXX 2.5 with a 3.3 engine and it shifted just fine when I put the motor in but now for some reason it wont shift to 2nd gear and runs at really high rpm's. Have it tuned perfectly and have put in a new 2nd gear drive hub and set the shift point as low as possible and flipped the drive hub around in both directions to see if I had it in backwards. I even put the whole 1st and 2nd gear assembly in a high speed drill and tested it in reverse and the 2nd gear dog came out and grabbed 2nd gear and it worked fine. It just wont work in the truck!! I just put in a new engine clutch, slipper is tight and the truck gets up to the speed where it should shift but it won't shift!!!! I have taken the trans apart at least 25 times to fix it and still isn't working right!! I am at a stand still and don't know what else to do. Was thinking about getting a 3.3 trans and just junk this old 2.5 tranny. Is it worth it to replace the trans with a 3.3 trans or keep banging my head against the wall with this old 2.5 piece of crap? If I should replace it, will the 3.3 trans drop right in or what?

  2. #2
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    You didn't mention tuning the engine. Go back to factory settings and try again if you haven't.

  3. #3
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    I have. Set it to factory settings and tuned it until it had a very snappy transition from low to high speed and does wheelies when ever you hit the gas. and there is a little smoke. it runs good, just won't shift

  4. #4
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    Does the 2.5 trans still have reverse?

  5. #5
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    I had a problem like that 2 years ago. what worked for me was I put a little oil in the hub and that fixed my problem. it has not gotten stuck on me since. shifts perfect.

  6. #6
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    i believe that under the support tab it will explain on how to change the shift points in the transmission. i looked it up and here is the link to help you on how to change the shift points on your tranny. but ive seen some people rip 2.5 tranny's apart with the 3.3 installed.
    http://traxxas.com/support/2-Speed-S...t-Adjustment-0
    Last edited by davyjones'_fleet; 01-23-2013 at 12:09 AM.
    EMBE
    Jato 3.3
    T-Maxx 2.5

  7. #7
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    Believe me I have tried all the support and books, but the thing still won't shift. I went as far as taking the shift ball and spring out and the thing still won't shift. And I have flipped the drive hub around both directions and it still won't shift

  8. #8
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    Yea. still stock

  9. #9
    RC Turnbuckle Jr. Snook Man's Avatar
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    If you took the spring and BB out and the pawl moved freely, you are starting off in 2nd gear. The stock adjustment is 6 to 6.5turns out from the adjustment screw being snug. Dont tighten the adjustment screw too tight or you will damage the spring and never get a reliable/consistant shift. The raised portion of the clutch should be visible to you when the clutch is installed on the shaft correctly, make sure that the set screw that attaches the clutch to the hub is tight and rests in the slot of the shaft.
    No slipper/tall gearing/power = broken parts.

  10. #10
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    Ok. well I think I'm just gonna go with the 3.3 tranny. with the 4907/4908 trannys, will the output shaft from my black transmission work in the new 3.3 tranny so I can use the same drive shafts and differentials.

  11. #11
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    I don't know about that, but I do know that the brake hex is a different size. I'm guessing that your driveshafts will work with the trans though.

  12. #12
    RC Turnbuckle Jr. Snook Man's Avatar
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    Quote Originally Posted by T-MANN View Post
    Ok. well I think I'm just gonna go with the 3.3 tranny. with the 4907/4908 trannys, will the output shaft from my black transmission work in the new 3.3 tranny so I can use the same drive shafts and differentials.
    No. The 2.5 output shaft will not fit the 3.3 transmission.
    You would need to install the model 4909 foc output shaft and use your current center shafts, or modify the shafts you have to use the 4908/7 transmission output. With the grey transmission (3.3 spec) you will also need to modify (dremel) the chassis for the brake caliper to clear the 4910 chassis.
    No slipper/tall gearing/power = broken parts.

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