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oil seal problem

Discussion in 'General Chevy & GM Tech Questions' started by dsfloyd, Apr 5, 2012.

  1. dsfloyd

    dsfloyd New Member ROTM Winner 1000 Posts

    Ok so my rear output shaft seal (aka rear transmission seal, extension seal or rear transfer case seal) started leaking. so I am thinking its an oil seal and those are pretty easy since I have done lots of them. Well this happens to be the oil seal from HELL. The replacing it was easy, but it keeps leaking. I have replaced it with a NAPA seal, an AC Delco (at $80:grrrrrr:), backed the seal out some and put gear oil RTV and re-seated, and just put in a Timken seal. All start leaking once I start driving. I made sure that all surfaces were clean etc (like I said I have done plenty of seals). even went back and made sure it was fully seated all the way around but still leaks. Its getting real frustrating so looking for ideas, since I am just thinking about putting some darn epoxy along the outside seal edge and TC housing. now looking at the TC housing the inside lip area is nice and smooth and round but the outer lip isnt nice and flat (but the sealing should be on the inside). The gun range will make me feel better for about 10 minutes but it will still be leaking.

    A little drivetrain back story: A while back I had the carrier bearing replaced. since then I would get a random knocking in the driveline. Looks like the driveline would somehow spin not like it should and was hitting on a lip on the bearing housing. Bending the lip back helped and it only did it once or twice more. I also noticed when I went to put the driveline back in that the drive shaft was not in a straight line horizontally and I had to do some work with the position of the bearing to get it to almost be nice and straight (assuming its the fault of the new bearing housing as that is when the driveline issue started). I am almost wondering if the driveline not being in straight damaged something a little at the seal and that is why I cant get it to seal properly.

    Everything is functioning properly except the seal so at this point I am just looking to see if anyone has any ideas on sealing the leak.

    Thanks
  2. dpeter

    dpeter Member

    What exactly is leaking? Is it where the seal seats in the housing where the two mating surfaces are not moving relative to each other or is it where the rubber lip seals against the rotating drive shaft?
  3. dipstick

    dipstick New Member

    Did you get drive line balanced after changing the carrier bearing? If you had to beat on line any will be out.
    Not much to a rear trans seal ..if it leaks mating surface must be bad. Drive line maybe messing seal up from the git go.
  4. dsfloyd

    dsfloyd New Member ROTM Winner 1000 Posts

    the leaking is at the mating surface of the seal and the TC.

    sorry wasnt super clear. the part of the driveline that was touching the carrier bearing lip was at a weld and you could see the rub, but wasnt on the tube and no dents. the lip on the carrier bearing housing was bent up to clear some room (the bearing and the "fix" were done at a shop". the rear mating surface isnt nice and smooth but but the inside is, but outside of finding a new TC rear housing. I figure its from when the driveline was not straight but it still wouldnt have hit the TC and the inside of the seal where the driveline goes through still looked good on the original leaking seal.
  5. dsfloyd

    dsfloyd New Member ROTM Winner 1000 Posts

    okay picture time
    oil seal.jpg bearing.jpg angle.jpg

    Pic 1 is the leak
    pic 2 is where the driveline was hitting carrier bearing (which may have also been because the driveshaft wasnt lining up straight
    Pic 3 is where I had to try and move the bearing over because the shaft wasnt straight.
  6. mfleetwood

    mfleetwood New Member ROTM Winner 1000 Posts

    Sorry, I am no help, but did want comment on your pics with the arrows and text. Very nice! It would be great if that could become the standard here :happy:
  7. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    Ugh, David, that is, indeed, the seal problem from hell. Given what you've tried, so far, I'm inclined to think use of a seal -plus- gasket maker might make sense ... and afterthat's dried (without driving the truck, yet), do an external seal using permatex or an epoxy as you'd mentioned.
  8. ippielb

    ippielb Active Member ROTM Winner 1000 Posts

    I have had the same problem on my 85' chevrolet silverado k10, i replaced the shaft seals on it, but it turned out it was the transmission main seal. So i replaced the whole transmission(tranny was blown anyways). Always lube up your seals.
  9. dpeter

    dpeter Member

    I would think that the drive shaft would have beat the snot out of the original seal and MAYBE been a little hard on the tail shaft. Could there be some hairline cracks where the seal is seated? A little far out there but given your background I would not suspect installation errors and have to start looking for unordinary problems.
  10. dsfloyd

    dsfloyd New Member ROTM Winner 1000 Posts

    I hope not, but sometimes life kicks you in the ______ (insert body part of choice). I backed the seal out a little and used the ultra black gasket stuff this time and tomorrow will re-coat the area again let it cure for 24 hours and drive it some on Sunday. Cant quite convince my self to epoxy yet but heres to crossing fingers. I know band aid approaches dont always work but heres to hoping that the lip on the TC got banged up and this will work this time.

    ---------- Post added at 09:30 PM ---------- Previous post was at 09:28 PM ----------

    Heres to hoping thats not the case. since I have been able to test it and clean every day its definately coming around the lip of the seal and just the autotrak fluid. But if this doesnt work it is on to bigger fixing.

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