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2003 update ML163 5 speed Auto gearbox oil leak

Discussion in 'Engine, Drivetrain, Fuel and Exhaust' started by oigle, Nov 1, 2012.

  1. oigle

    oigle Senior Member

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    Currently 2003 ML270. 2012 Nissan Maxima 250SL.
    No problems as yet with operation but have noticed an unacceptable oil leak from the tranny. The sump is quite wet and the plug situated at the front d/side corner above the sump level is also wet. Have a feeling I have seen reference to this problem before causing electrical issues. I have none so far but would like to prevent same occurring.
    Could someone tell me what the issue is and perhaps give me a WIS for the necessary repair as my garage man is not MB trained.
    Thanks in advance.
    Ian.
     
  2. Cole@MBS

    Cole@MBS Forum Supporter Authorised Forum Supporter

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  3. OP
    oigle

    oigle Senior Member

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    Thanks Cole. Much appreciated.
    Ian.
     
  4. OP
    oigle

    oigle Senior Member

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    Currently 2003 ML270. 2012 Nissan Maxima 250SL.
    Purchased the pilot bush and did an oil change whilst at it. Oil was very black and a bit smelly after only 60000km since last change. Obviously towing in warm conditions doesn't do the oil any favours.
    When fitting the bush, it turned out that the bush seals were not at fault. It was the O ring on the electrical plug that had failed......guess what - the electrical plug is part of a $900 electrical harness!! Decided that we wouldn't go down that track so have arranged to remove the O ring and "rope" it. Seems my mech prefers that to trying to source a suitable O ring replacement. Haven't got it back yet but he assures me it is a good way to repair it.
    What do you guys do in this situation?
     
  5. star

    star Forum Supporter Authorised Forum Supporter

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    There shouldn't be any oil getting to the electrical plug, that's just to keep the water out. If it were it would allow oil to travel into the loom.
     
  6. OP
    oigle

    oigle Senior Member

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    I can see I'm going to have to look for myself. The info I got was - the seals on the pilot bush were OK - replaced it anyway - but the article that plugs into the pilot bush also has an O ring seal which was flattened and was leaking.
    I went to MB with that info and they said the only plug they could see was part of the electrical loom as mentioned. Maybe there is some misinformation here.
     
  7. OP
    oigle

    oigle Senior Member

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    Can someone explain to me how this plug etc works so I can check it out tomorrow? Maybe a diagram of how it goes together? I gave the writeup to the mech and he seemed to have no trouble with that. Just said it was leaking oil from the other seal - not the one around the pilot bush.
    When I looked at the pilot bush, it appeared to have holes in it which would allow oil into the inside - could be wrong but that was impression I got when I glanced at it.
     
  8. star

    star Forum Supporter Authorised Forum Supporter

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    ???

    Yes you got it wrong, no oil should be that side of the bush.

    I could take some pics if you like?
     
    Last edited: Nov 7, 2012
  9. OP
    oigle

    oigle Senior Member

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    Thanks for the offer. If I can't sort it today myself, I might ask for that. Thanks for the info re oil on inside of bush.
    Its a bugger when you live in an area without trained MB techs. Thought this would be a simple job...

    Ian.
     
  10. OP
    oigle

    oigle Senior Member

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    Star - sent you a PM. Hope you can help.
    Pilot bush that came out - part number A2035400253 - is like a colander. Lots of holes through the inner face of the part. Oil is getting through these holes and then leaking from the seal around the outer plug. From what you say, this area should be dry. What is supposed to stop the oil getting into the bush? Is there another part inside the case that is supposed to seal this area?
    Totally confused.....
     
  11. Uncle Benz

    Uncle Benz Senior Member

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    The "colander" holes allow the electrical pins to poke through. 2 o rings on the pilot bush. One keeps oil inside the gearbox and stops it falling on the ground. The other o ring keeps oil away from the pins and electrical plug. If the pilot bush has been replaced with both o rings on it your troubles are over.
     
  12. star

    star Forum Supporter Authorised Forum Supporter

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    As UB says, one seal locates against the gearbox case and the other inside the conductor board. The hole allows the pins thru (which sit in a cup on the board). The new seals on the adaptor plug are black and the old type are are see thru white. Hope pics help.
     

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  13. OP
    oigle

    oigle Senior Member

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    Thanks for clarification re holes. Unfortunately, it is still leaking oil. The inside of the bush is full of oil. Yes, it has 2 O rings. Both on outside. How does the 2nd O ring keep oil away from the pins. O ring is on outside - pins are inside.
     
  14. OP
    oigle

    oigle Senior Member

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    Glad you guys are still out of bed.....
    I have forwarded this link to my mechanic. Hopefully, your info will help him to sort it out.
    Thanks a lot guys.
    Ian.
     
  15. star

    star Forum Supporter Authorised Forum Supporter

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    The adaptor plug is very tight, make sure it's well lubricated when fitting and the oil seals were removed. Also the oil maybe leaking from the loom if it has been soaked in oil for a while.
     
  16. OP
    oigle

    oigle Senior Member

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    On inspection, it would seem that everything has been done correctly and your suggestion that the oil might be draining from a soaked loom could be right. Mech has now spray cleaned it thoroughly with electrical contact cleaner after hanging it for a few hours to hopefully drain any excess oil out. Is going to put everything back together and I'll road test it over the next few weeks - taking van up the coast for 4 weeks. Hopefully it will be nice and dry!! That is both the weather and the sump :D
    Thanks for all your help.
    Ian.
     
  17. television

    television Always remembered RIP

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    Thanks Star,,,,,how easy to forget the fluid running back down the wire :D
     
  18. soup nazi

    soup nazi Senior Member

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    Oigle
    How did this turn out, still leaking? My tranny has recently started with a leak from that data plug and i want to fix it up.
     
  19. OP
    oigle

    oigle Senior Member

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    Finally got it right. The original seal I bought continued to leak and it got to the point where we had to start blaming the seal. Even after draining the loom, oil was still leaking. So, bought another seal and very carefully fitted it.
    So far, so good. Hasn't leaked since and it has been a few weeks now.
    Have since fitted an extra oil cooler to the tranny too. Fitted it into the standard system with the oil going through the new cooler first and then back through the heat exchanger. Yet to tow since fitting but am sure it will help. Oil was quite black after about 70K from last partial change at 60K. No good. Hopefully will stay clear now.
    Seems the leak from the electrical plug is very common. My only advice is to be very careful not to damage the seal in any way when fitting. Couldn't see any marks on it at all but it leaked!!! It is actually a fairly quick easy job to do.
    Best of luck.

    Ian.
     
  20. soup nazi

    soup nazi Senior Member

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    Just one question on this job. Is there anything that can come off inside the gearbox with the bush out? I took my car to a Benz Tech and he says you need access to the inside and outside of the box to do the job properly and it requires a new filter and oil change since the pan will be off. Personally I don't know anything more than what I've read here. I have just moved to Cairns and the chap I spoke with is no longer working with MB anyway.
     
    Last edited: Feb 22, 2013

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