Lv 4
Joe asked in Cars & TransportationCar MakesFord · 1 decade ago

'94 Ford Explorer. ATF in oil?

'94 Ford Explorer V6 4X4

I've asked mechs. about this and they all say it's not possible for ATF to leak into the engine, basically I must be an idiot who's not paying attention to what he's pouring and where. I agreed that it shouldn't be possible and assumed I made a mistake.

Since then I've changed my oil 6 times very carefully. Reading the labels and smelling the oil before pouring it in.

Also I have had to add ATF to the trans. about 1-2qt. per week.

When I drain the engine oil. there has been way too much and it's reddish and smells like ATF.

So don't bother telling me it's not possible and start looking outside the box and consider how it might be possible.

Let me repeat: THIS IS HAPPENING

How MIGHT it happen?

Thanks for anything you can think of.


It does smoke like hell esp. when I start it. And I noticed a vacuum line is missing. Thanks again.

6 Answers

  • Ron B
    Lv 6
    1 decade ago
    Favorite Answer

    There is only two ways ATF can get inside an engine without being poured in there. One is through a vacuum hose attached to a modulator valve, which I'm not sure that you have. If that were the case the engine exhaust would SMOKE like hell and would have to empty the tranny to have a chance to make it past the piston rings and in to the crankcase. Second way would involve the occurance of two problems at once. First the transmission cooler would have to be leaking ATF into the coolant and then the coolant would have to be leaking into the crankcase. I bet someone is messing around with you and pouring the ATF into your engine.

  • Anonymous
    1 decade ago

    Assuming no one is messing with your vehicle, the vacuum hose from the modulator is the only normal way. Extremely improbable but did you inspect the cooler lines very closely? A cooler line rubbed through the oil pan is the only other possibility that comes to mind, unlikely to do what you describe with no external leaks, but worth a look. I've seen stranger things that would verge on the impossible yet were true. Like a piece of plastic cutting a steel line with no damage to the plastic, etc.

    Good luck!

  • 4 years ago

    I'm afraid this one is a bit of a stumper, but if you do that, you should check if your coolant lines are fine. One possibility that I can think of is that your transmission cooler, if it's built as a part of the regular radiator, may be leaking into the coolant, and that's how it's getting into the engine, but that doesn't explain how it's getting into the oil. Since coolant should never meet oil, much less end up in oil. I'll have to conclude that there's something not kosher with your engine's "plumbing", if you know what I mean. ;-) When's the last time you had your transmission 'serviced'?

  • 5 years ago

    My modulator valve was bad and taking in trans fluid through the vacuum line and raising the oil level 94 4.0. Even though it seemed to shift fine it would still take in about a quart of trans fluid every two weeks. Best way to fix is through the access panel on the interior. You would have to take out seats, console and pull back carpet but I think it s easier than taking off cat and laying on your back.

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  • 1 decade ago

    it could be a vacuum problem it has happened before to vehicles ive even seen trani fluid come into the cooling system through the vacuum lines it does happen on the older explorers and rangers

    Source(s): i am a master parts consultant for ford
  • Anonymous
    1 decade ago

    ok well.. something most mechanics wont tell you.. Im one so here I go....

    any tranny fluid can be a substitute for oil as long as its less that 25% of the total oil.. in high millage engines we throw in a quart of ATF, DEXRON III/MERCON or ATF+3 (same as ATF) to help remove sludge build-up in older cars when you change the oil... insted of 4 quarts of motor oil.. 3 quarts+ a quart of ATF.. so tranny fluid in the engine isnt a major problem.. just aslong as it isnt more than 25% transmission fluid your fine

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