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homerbw's avatar
homerbw
Explorer
May 12, 2016

Ford 4R100 Transmission

I have either a 1999 4R100 or 4L100 transmission which works great but sometimes won't fully downshift into low when I come to a stop. I can still get it to shift if I slowly coach it forward. Once in transit everything shifts great. Anyone have any ideas what might be going on? The engine is a 1999 Ford Triton.
Class A

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  • NAUTIQUE's avatar
    NAUTIQUE
    Explorer
    May 12, 2016
    Homerbrw,
    Might want to check out:

    TSB#02-11-3 * 4R100 Tranny Hard/Eratic shifting.
    Powertrain Control Module (PCM) gets bad info from Speed Sensor.
    Ford has a new ground cable that is added to PCM.
    Cost me +/- $160 installed by Ford Truck Center.

    Click the F53 link in my sig & there should be some more info with link to the Ford TSB's
  • crasster's avatar
    crasster
    Explorer II
    May 12, 2016
    I would go to a Ford forum and ask some of the experts if they think a bit of Marvel Mystery Oil in the tranny fluid would help unstick things. That stuff is incredible for cleaning things out.
  • carringb's avatar
    carringb
    Explorer
    May 12, 2016
    Likely a sticking valve body solenoid. Try a full transmission fluid exchange. Hopefully that will free things up.

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