'08 GT 5-sp trans leak

Discussion in '2005+ Mustang GT 4.6L Tech' started by Lannyl81, Jun 10, 2021.

  1. Lannyl81

    Lannyl81 Junior Member

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    Not at all....in fact the flange seal looks fine...nothing torn at all. I did noticed that my electric impact wrench had absolutely no problem in getting the flange nut off...makes me wonder if a previous owner was in here and did not torque the nut down and it had come loose. Also noticed there was a circle of the nylon lock material coming-out of the nut before I removed the nut.
     
  2. SPeace-ATL

    SPeace-ATL forum member

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    The "curl" of the nylon material flopping from the nut doesn't hurt anything, but I agree that it indicates the nut has been off.

    It is possible that the nut could be loose enough to be leaking. My little Makita battery impact seems to only tighten to around 20-22 ft/lbs. It could never remove one of those flange nuts, but not all little impacts are the same.

    It could indeed be that it was simply loose. Look for nicks and burrs where that flange seal mates the output shaft and the seal lip on the flange.

    Some builders routinely glob RTV under that washer saying that way there will never be a leak there! I like things clean and original, so I find it a royal pain to scrape that sealant out of the hub of the tail flange. However, one must do what ya 'gotta do' to finish the job!

    On removing the rear seal, the tail housing is always off for me, so I use a big open-end wrench and just pop it out. The original rubber clad seals come out pretty easily. It is those metal-rim aftermarket seals that are a big pain to wrestle out! I've always thought I might try screwing a drywall screw into the seal and then use a claw hammer to pull it like a nail if I had to remove one with the shaft still in the middle.

    Like I said the OE seal comes out without much stress. Hmm, you could probably angle a large screwdriver through the inner lip and flip it out. But when prying like that it is possible to put a big scratch in the bore that might cause seepage around the outside of the new seal. If you do see a scratch, smooth it out and rub a little sealant in the groove to be sure it seals.

    Stan
     
  3. Lannyl81

    Lannyl81 Junior Member

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    I might go ahead and remove the extension housing, have to see if I can get the shifter connector (have no idea what it is called) off first....a bit tight up there, probably have to lower the back of the trans a bit.

    And if I do, what is the recommend sealant to use? I have several types of RTV but not sure if any are good for ATF.
     
  4. SPeace-ATL

    SPeace-ATL forum member

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    My preference is Permatex Ultra-Black. It seals well, but does not dry up so terribly hard.

    Those super-duper sealants dry hard like epoxy and make it really hard to get apart and really hard to remove the old epoxy to seal it again next time.
     
  5. Lannyl81

    Lannyl81 Junior Member

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    Thank you...that is what I normally use.
     
  6. Lannyl81

    Lannyl81 Junior Member

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    Thought I would update this thread....
    Replaced the output shaft seal and the output flange nut seal. Followed the instructions above to get the flange on, removed the nut, then put the seal on and torqued it to 105 ft-lb. Put driveshaft back on, took for a short drive, got under it and no leak...yeah! Parked the Mustang in a neighbor's garage and worked on the peeling door panels.

    Jump forward about four weeks, took Mustang out for a drive after getting the door panels back on and when I moved the Mustang to go back to neighbor's garage I find a small puddle of trans fluid on the floor....CRAP!!

    I am hoping that the output flange nut came loose and just needs some thread locker since the nylon thread lock is probably worn-out.....at least that is what I am going to try. Will need to look at the extension housing again...make sure it is not cracked afterall.
     
  7. Lannyl81

    Lannyl81 Junior Member

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    Update #2: had one droplet hanging off the tail housing, just below the output shaft. Removed the driveshaft from the output flange and expecting to get a nice dribble of trans fluid out...I got nothing...all dry. Put the driveshaft back on.
    My only guess is that I tore the output flange seal somehow installing the output flange. I put ATF on the seal lips, cleaned the output shaft...but I must have done something wrong...somewhere.
    I currently have the Mustang on jackstands, rear wheels off, let the engine spin the rear for a minute or so. Checked it and no drip...so I waiting to see what happens as it cools down.

    I need a better method of getting the output flange back on?

    Update #3: no drips after three hours of cooling-down. Put rear wheels back on, dropped it off of jack stands.
     
    Last edited: Jul 30, 2021
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