Change transmission fluid or not?

Discussion in 'General Motoring' started by Joseph Osborne, Feb 12, 2004.

  1. I have a 92 voyager, 150,000 miles. I have had it for the last 100,000
    miles and have never changed the transmission fluid. This is because I have
    heard that once it has been let go that the fluid thickens and putting in
    new, thinner fluid may cause valves to leak and shifting problems.

    Is there any truth to this? Should I change fluid or am I risking
    catastrophic failure? I plan to keep the van at least another 50,000 miles.

    The transmission works perfectly most of the time but occasionally will get
    stuck in second. Turning off the ignition and restarting the engine has
    fixed this each time so far.

    Joseph Osborne
    Carlisle, PA
    Joseph Osborne, Feb 12, 2004
  2. Joseph Osborne

    Carl Baron Guest

    It's advisable to change the transmission fluid and clean the screen every two
    years. Supposedly, the best thing to keep from having transmission trouble.
    You're way overdue.
    Carl Baron, Feb 12, 2004
  3. Joseph Osborne

    Bob Shuman Guest

    My opinion:

    If you do not change the fluid AND FILTER, you are going to have a major
    problem in the not too distant future. The fact that your vehicle is
    already going into "limp mode" (2nd gear) occasionally is a sign of trouble.
    If you are lucky it is because the dirty filter is restricting fluid
    flow/pressure. I'd do this/get this done ASAP and hope the existing problem
    goes away. if it does not, you will have a major expense of
    rebuilding/replacing the transmission.

    Bob Shuman, Feb 12, 2004
  4. Joseph Osborne

    clare Guest

    Cnamge it. If it fails it is not because of the new fluid - much more
    good done by changing than by not.
    clare , Feb 12, 2004
  5. Joseph Osborne

    Steve Guest

    ABSOLUTELY change it, using the correct fluid and filter.
    Steve, Feb 12, 2004
  6. Joseph Osborne

    John Kunkel Guest

    Some recommend against fluid changes in high mile units.
    John Kunkel, Feb 12, 2004
  7. Some recommend smoking 2 packs of cigarettes a day and only ever eating
    McDonalds. You can find all kinds of stupid and wrong advice out there.

    The original poster is long overdue for a fluid and filter change. By
    changing now, he *may* forestall transmission repair. By failing to do so,
    he's headed for an expensive repair.

    Daniel J. Stern, Feb 12, 2004
  8. Never heard that one, but it sounds like an old wives tale.

    I'd change the oil and filter and probably wouldn't be a bad idea to
    have it flushed with a good system such as Wynns.

    Matthew S. Whiting, Feb 12, 2004
  9. I'm not a tranny expert or mechanical engineer (I am an engineer, but
    electrical), but this is one of the most hokey things I've read. If the
    clutches are so badly worn that they are depending on junk in the oil to
    function, the likely other parts of the transmission such as the oil
    pump and bushings and bearings are also shot and the dirty oil is just
    accelerating their demise. I'd change the oil and if the tranny stops
    working then it was due for mechanical repair anyway. Leaving
    contaminated fluid in it only ensures a catastrophic failure in the
    future, probably in the middle of nowhwere, at night, in a thunderstorm.
    You make the call, as the IBM commercials used to say.

    Matthew S. Whiting, Feb 12, 2004
  10. Joseph Osborne

    Steve Guest

    Just my opinion, but that's urban legend nonsense. Even if the unit
    fails because it was somehow magically being held together by sludgy
    fluid then you're better off KNOWING that it was shot rather than
    stranded somewhere.
    Steve, Feb 13, 2004
  11. My Father once had a 1963 Plymouth Valiant, which he bought when it
    was 5 years old, with 93,000 miles on it. At about 110,000 miles, we
    decided to change the fluid. The transmission was working fine at the
    time. About ten days later, the transmission experienced a major leak
    while driving home from work on the freeway. A rebuilt transmission
    was installed.

    We were left to wonder if the same problem would have occured if the
    fluid had not been changed. Without knowing the car's history, we
    could only guess that the fluid had never been changed. In those days,
    the owner's manual did not specify a change interval for cars in
    *regular* service. I am for changing the fluid on a regular basis, but
    can fully appreciate Joseph's concern.

    -Kirk Matheson
    Kirk Matheson, Feb 17, 2004
  12. Probably not, but this "major leak" was probably not the result of
    changing the fluid, per se. It also probably did not fatally damage the
    transmission -- it sounds like your father was the victim of a
    less-than-competent and/or less-than-honest mechanic. Transmission fluid
    changes themselves do not (cannot) cause sudden catastrophic external
    fluid leaks, and sudden catastrophic loss of automatic transmission fluid
    does NOT cause the rapid destruction of the transmission as does sudden
    catastrophic loss of engine oil.

    1963 was the last year for the external trans fluid filter P/N 2400124 on
    Chrysler products. It was clamped to the driver's side
    engine-to-transmission bracket of your Slant-6 engine, and the
    transmission fluid lines were threaded into the filter with a male 3/8"
    IV-flare fitting on the upstream side and a female 3/8" IV-flare fitting
    on the downstream side. Such is the alignment of the hard lines that it
    is VERY easy to cross-thread these connections without realizing it.

    Assuming no plain old stupid error was made, such as leaving the
    transmission pan drain plug loose or overly tightening it -- 1963 was also
    the last year for a factory-installed pan drain, or leaving the torque
    converter drain plug loose or overly tightening it -- 1977 was the last
    year for torque converter drains -- then the most likely cause of your
    sudden serious leak was an improperly connected external trans filter.

    It's almost certain your father's car did not require a rebuilt
    Yes, actually, it did. 1964 was the first year transmission fluid was
    designated a "lifetime" item for vehicles in "regular" service. In 1963,
    the change interval was still a 3/36 or 2/24 item, depending on whether
    the vehicle was in "regular" or "severe" service, and this was stated in
    the owner's manual.

    Daniel J. Stern, Feb 17, 2004
  13. Depends on where the leak was. If it was at the pan gasket, then, yes,
    this IS a case where the oil change was a contributing factor ... but
    ONLY because the mechanic didn't replace the pan properly! However,
    that isn't the fault of the fresh fluid or the new filter.

    Matthew S. Whiting, Feb 17, 2004
  14. And no doubt that change had more to do with marketing than with any
    engineering change.

    Ted Mittelstaedt, Feb 18, 2004
  15. Yeah, the only engineering change for '64 was the replacement of the
    in-pan screen/in-line filter with an in-pan Dacron filter of the type with
    which we're all now so familiar.
    Daniel J. Stern, Feb 18, 2004
  16. Joseph Osborne

    robs440 Guest


    robs440, Feb 20, 2004
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