By on March 26, 2012

 

 

Dan R writes:

Hello Sajeev,

I have a transmission related question that I was hoping you may be able to assist me with. I have a 2003 Mustang GT, 4.6, Auto. 110k. (3rd owner) The car has the occasional classic Ford “AOD trans shudder” at lower RPM under load.

It does not really affect the overall drivability of the car but is an annoyance and I’d like to take care of it. As far as I know this car has never had a trans service done. I’ve heard mixed reviews on weather to do a trans flush or not.

Would it be advisable to take it to a shop to do a “power flush” or whatever they are calling it, or should I do it myself? I normally do all my maintenance myself.  I have no problem dropping the pan and making a mess, I just want to make sure it will clear up the fluid in the converter.

So, any advice is appreciated, thank you!

Sajeev answers:

I have yet to officially choose a side in the battle between power flushing and the normal fluid/filter change. I like power flushing since it blows out fluid from the torque converter, and you have no other choice.  Why?  Because the bean counters at Ford “thrifted out” the torque converter drain plug (circa 2000) but still left us the rubber access grommet for no good reason…other than being too cheap to thrift that part out, too.

And for classic Ford tranny shudder, you need to change all the fluid, including the converter. I personally know Ford transmission shudder, as I moderate the best Lincoln forum on the planet: a place where Lubeguard Red was/is mentioned regularly. I used it for a Ford tranny shudder many moons ago, and it worked like a charm.

Even at this high-ish mileage, a fluid/filter change and adding Lubeguard Red is a good idea. And now I cursed it: with my luck, my advice means that new fluid will burn out the (excessively worn?) clutches and make things much worse.

Fingers crossed that I didn’t screw the pooch.  I hate automatic transmission problems.

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12 Comments on “Piston Slap: Lubeguarding against Ford Tranny Shudder?...”


  • avatar
    GS650G

    I would do a phased replacement of a few quarts every time the oil is changed, maybe 3-5 quarts out of the 12 that are in there.

  • avatar
    Zackman

    Just shut off the Overdrive at lower speeds and problem solved. My son owned a 1997 Mustang and had the same issue. That’s what he did.

  • avatar
    Ubermensch

    I am not aware of any shops still using “power flush” machines. Most have switched over to fluid exchange machines like ones made by BG that use the transmissions own pump to move the fluid. I would use a shop that has a fluid exchange machine and get almost 100% fresh fluid.

  • avatar
    relton

    Note that this transmission ow requires Mercon V, despite what it says on the dipstick and in the owner’s manual.

    Ford had a major TSB on just this issue. Mercon V was made specifically to help eliminate the torque converter shudder.

    In my older Fords (Mark VIII, Cougar) the manual also recommended transmission fluid changes about every 30,000 miles. They aren’t kidding: performance dropped off noticeably after about 40,000 miles.

    Quite a change from my GM cars, where the transmission fluid lasted over 300,000 miles.

    Bob

  • avatar
    gkhize

    I have a ’96 Mustang GT and experienced that very issue. A friend at the local Ford garage told me it simply means a fluid change is required. I did mine myself in the garage and changed the filter as well. Granted I was not able to get all of the fluid out since just dropping the pan does not dump all the fluid out. However, it did resolve the issue and I have not had any further issues. Did the change at just under 100K miles and am now up to 175K with no recurrence.

  • avatar
    turtletop

    Is the shuddering issue a result of a disintegrating torque converter?

    I have an E4OD transmission in my Econoline. A few years back, I was getting a noticeable shudder while idling in drive. On the advice of a local trans rebuild shop, I bought and installed a rebuilt torque converter, along with a new filter and pan gasket. I also performed what amounted to a fluid exchange by using a transmission cooler line to pump old fluid out while I added new. Many, many quarts of transmission fluid later, the shudder was gone and hasn’t returned in over 20K miles. The transmission has worked flawlessly since then… so far, so good. The parts and fluid set me back about $500, a fraction of what a rebuilt transmission would have cost.

    So, a question: Might a failing torque converter the root of the AOD shuddering problem? If so, will doing just a fluid change and addition of Lubeguard only buy a bit of time?

    • 0 avatar

      Its only the fluid that is the problem. Well perhaps Ford shoulda designed their parts to work with the Mercon fluid’s requirements in the first place, but that seems less likely…

      In theory, I have my doubts that your Econoline’s convertor really was bad. Usually the fluid swap is all you need.

    • 0 avatar
      nikita

      The E4OD was another Ford horror show. Issues were different than the AOD, in that a different fluid spec wont bandaid the defects. Numerous internal changes are done at rebuild time.

  • avatar
    golden2husky

    Seems like this problem is not limited to just a few models. My 20 year old Sable has that shudder. Trans only has 120K plus miles but the first 13 years only produced 40K or so of the miles so there is a lot of shifts on this trans. Sajeev, should I drain out the fluid. I am assuming I still have the drain plug in the converter. Any chance the change will kill the trans?

  • avatar
    blowfish

    ya is very true, when car is new, u can run the OD/ 5th gear from a dead stop, but after a few yrs it may not be able to handle the extra torque.
    One dude told me he never run his 90s F250 dsl on OD while in city, it does make sense esp when the OD is being upshifted early as to save fuel, but u maybe inadvertently using the premature wear of auto box
    ( which lead to earlier rebuild ) to pay for it!

    Is OK as long as u trade her in every 3 yrs, just leave her in the D pos and let the computer to do all upshifting.

  • avatar
    Moparman426W

    Like a couple of others said, in city driving just put the shifter in drive instead of OD. That was how my mom drove her Mark V11 for 12 years Never had a problem with shudder driving it like that, plus it saves alot of wear and tear.

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