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When the vacuum modulator goes bad.

Discussion in 'Under the Hood' started by Hank, December 8, 2004.

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    1. Hank

      Hank Elite Explorer

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      Yes, I already know the modulator is bad.

      The question is how/where does the transmission fluid get pumped into the engine oil?

      When the modulator goes bad fluid is sucked up the vacuum line and should be sucked into the intake and burned off. Where am I brain fading on this one...

      No crisis, part is waiting for me yet again at AutoZone. 2nd modulator in 5 yrs... Just currious.
       
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    3. chowder

      chowder New Member

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      what specifically went bad to tell you that it is the modulator?????? i have a 93 and am praying thats all thats wrong with mine.
       
    4. Brain

      Brain Active Member

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      Engine oil and tranny fluid shouldn't come together as they are separate systems. They are always separated by at least one other thing (air, coolant, metal, etc.). I can't think of how tranny fluid and oil got mixed except by putting one or the other in the wrong filler hole.

      Did you see tranny fluid in the engine oil?
       
    5. MrShorty

      MrShorty Explorer Addict

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      I think it's the same mechanism by which fuel gets into the oil when the engine runs real rich. Piston rings don't seal perfectly, just well enough. When you have excess fluid (gasoline, tranny fluid) in the combustion chamber, some gets past the rings where it gets into the oil. If that's not it, someone speak up, but I think that's right. At least part of the explanation anyway.
       
    6. Glacier991

      Glacier991 EF Tranny Guru Moderator Emeritus

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      I'm at a loss, other than Mr. Shorty's explaination.... even then I am doubtful. I guess I too want to know how you think it is getting in the engine oil... more typically it is just burned along with the fuel charge.
       
    7. Hank

      Hank Elite Explorer

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      Chowder, pull the vac line that comes up from the trans to the T located on the drivers side of the engine, if it is full of red stuff it is leaking.

      Symptoms, strange shift patterns, loosing fluid without visible leaks, rising oil levels..

      Took about 1hr to replace including changing engine oil. Tip, while you are there replace the little sections of vac line on each side of the circuit.
       
    8. chowder

      chowder New Member

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      thank you very much for your help. i have a strange shift problem with my x and my ex LOL. anyhow, i think im going to skip the diagnosis. the truck either has 116k or 216k, nobody really knows. and if i need a new tranny, im not hurting anything by putting a new modulator on it. i think im going to go ahead and try to replace nearly all of my vacuum lines, as some of them are starting to look pretty shabby. does anyone know what sizes and overall length i will need for this? it would help if i only had to make one trip to the parts store, and i dont like working under hot hoods.
       
    9. bme107

      bme107 New Member

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      I'd be interested in finding out myself.
       

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