Gear won’t engage

Discussion in '2005+ Mustang GT 4.6L Tech' started by Mark Bomgardner, Sep 21, 2022.

  1. Mark Bomgardner

    Mark Bomgardner Junior Member

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    I inherited my fathers 06 mustang. It has lots of work done to it as he drag raced it mostly. The transmission is the automatic but built to take on the higher horsepower. I was driving it this morning and accelerating when the transmission disengaged. Acting like neutral (revved up high). I had it towed home. Park keeps the car in place, reverse allows it to move forward or backward, neutral works normal and drive only allows it to move forward. I’m thinking the shift linkage came undone or maybe something with the draft shaft. Does anyone have a helpful direction to look at? I took apart the center console and got the shifter assembly apart. I just can’t see where the linkage goes to. Thanks.
     
  2. 07 Boss

    07 Boss Senior Member

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    Wait, so your car moves forward when in reverse, as well as backwards??? And what other direction did you want the car to go in when in drive? It should only go forward, no? I'm really confused to what your issue really is.
     
  3. Mark Bomgardner

    Mark Bomgardner Junior Member

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    It only rolls if I push it; not under throttle.
     
  4. 07 Boss

    07 Boss Senior Member

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    So when you push the gas in reverse does it move? And in drive does it move forward when you press the gas?
     
  5. Mark Bomgardner

    Mark Bomgardner Junior Member

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    No, when the throttle is hit, it just revs in all gears; no movement. The only movement noted in the original post is if I push the car itself.
     
  6. 07 Boss

    07 Boss Senior Member

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    Actually sounds like something along the lines of busted input shaft or blown out torque convertor. But, first follow the cable from the shifter to the tranny and make sure it is moving the lever on the outside of the tranny. I doubt that is it because you said you were driving when it happened and I don't think the linkage broke and shifted itself into neutral at the same time. Either that or a catastrophic failure of the transmission but I kinda doubt that just because you lost all the gears at once.
    You said the transmission was built. What exactly was done to it? Did it include a 300M input shaft or aftermarket convertor? What kind of power does the car make?
     
  7. ESP41

    ESP41 Junior Member

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    Lets start with the most likely candidates. If you noticed the trans slipping when in gear before the failure, you like have the trans as the source of the problem. Another possibility on a drag car is a busted flywheel. Try removing the few bolts that hold the transmission inspection cover on (it is under the transmission where it butt up to the engine). There may be some loose metal pieces in there from the flywheel.

    Of course, all this assumes the driveshaft did not fall out of the car.
     
  8. Mark Bomgardner

    Mark Bomgardner Junior Member

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    I went through my dad's records and it shows a TCI 5R55S SuperStreetFighter transmission with a M300 input shaft and billet aluminum servos.

    I never noticed the trans slipping while driving and when the problem occurred, i heard a faint pop. No metal-on-metal, no exceptionally loud noise and no vibrations.

    I partially removed the shifter assembly out last night and there seems to be some play with the linkage on the trans side but I am not sure if that is normal or not. I didn't have time to remove the assembly completely so I couldn't see too much. Is it normal to have play in the linkage?

    I checked the driveshaft last night also and there is no play and doesn't seem to be an issue.

    I've attached a list of the performance parts he had listed. The main ones I see are the 4.10 gears, PTC 3200 Stall Torque Converter, Camshaft kit, trans, Dual fuel pump with 60lb injectors, and the Stage 2 Procharger. I am not sure of the power exactly but I believe he told me just over 600.

    I may have to try and check out the flywheel.
     

    Attached Files:

  9. DieHarder

    DieHarder Senior Member

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    First blush sounds like something broke. The shifter linkage moves a cable that runs under the car to a selector lever on the transmission. If you verify that it's moving the selector lever on the trans and nothing else is obvious it may be time to get a second opinion.

    Here's a diagnosis/troubleshooting procedure from the manual that might be helpful:

    https://iihs.net/fsm/?d=242&f=Diagnosis By Symptom.pdf
     
  10. 07 Boss

    07 Boss Senior Member

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    I definitely think it's something between the motor and tranny as opposed to the actual tranny. Flywheel, convertor, or input shaft.
     
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