I own a '99 Ford Explorer and have had a problem with loosing transmission fluid. The only problem is it doesn't leak out..... I called around and found someone who told me it could be a modulator valve that is busted and the fluid gets sucked into my engine. Two questions...... How will this affect the engine (problems in the future?) and how extensive are the repairs(i.e. is this a do-it-yourself or shop job)?

 

I'm not real familiar with the newer Explorers, but I was of the impression that the '95 and up transmissions were all electronically controlled. Thus there would not be any vacuum modulator. Vacuum modulators were only present on the '91-'94 Explorers with the A4LD transmission.
To add my own speculation, is it getting into the transfer case (if 4WD)?
Into the coolant through the "ATF cooling line" in the radiator?

 

no 4wd. Wouldn't the cooling make it run like crap? it runs fine as long as i keep pooring fluid in it.

 

Not necessarily, but you should be able to tell if the coolant level is changing, or if there is ATF in your overflow reservoir.
On a 2WD, I don't visualize any other "internal" ATF leak. How much fluid are you losing?

 

i am loosing about 2 quarts a week. it doesn't overheat and there is no red liquid in the overflow. I called my local transmission guy and he agreed with you. there is no vaccum modulator. I guess i will have to shell out the cash for this puzzling problem. Thanks for responding!