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MARK_VANDERBENT's avatar
MARK_VANDERBENT
Explorer
Apr 02, 2018

Trans fluid change on my 2007 suburban with 320,000 miles.

I bought a high mile suburban and the as far as I know it's the original trans, and I have no idea when the fluid was changed last. It is pretty dark but not burned. The truck shifts perfect and shows no signs of a problem. I have heard don't touch it, because new fluid may shock it into problems. I want to introduce a bit of Lucus, but fear this may clean out and dislodge sludge. What you all think?? Change it? Or. Leave it alone? Oh and yes I tow a trailer with this truck.
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  • carringb's avatar
    carringb
    Explorer
    Apr 02, 2018
    I agree with avoiding a pressure flush.

    You should drain and re-fill. Sometimes this can dislodge sludge or debris, causing near-immediate failure. If this happens, keep in mind it only accelerated the inevitable. Better find out before a long trip.

    FWIW - I've gone to 100,000 drain and fills on my transmission. I'm a little over 450,000 and I'm a little over my 100,000 interval now. I just run the Napa stuff meeting factory spec.
  • Fordlover's avatar
    Fordlover
    Explorer
    Apr 02, 2018
    My uncle's 2003 explorer has 350K on the original transmission, and he has them drain, swap filter, and refill. No special additives. Best of luck.
  • FishOnOne's avatar
    FishOnOne
    Nomad
    Apr 02, 2018
    Drain the fluid and change the filter. Do not flush and do not add any additives.

    Good luck...
  • Big_Katuna's avatar
    Big_Katuna
    Explorer II
    Apr 02, 2018
    Hope you got it cheap. I’d be shocked if it hasn’t been rebuilt. I’ve had several Burbs and Silverados and rarely got 150k out of a tran.

    I’d change it and be ready to rebuild it.

    My sons 2002 Chevy 1500 just failed last week. 180k.
  • coolmom42's avatar
    coolmom42
    Explorer II
    Apr 02, 2018
    General advice I've heard is to drain it and refill with new fluid, as opposed to a flush. Depending on the vehicle, you will get about 1/3 of the fluid or more. Do this a few times in a short time span and you will have mostly new fluid. This doesn't disturb wear particles like a flush will.

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