Auto Question: Leaking ATF but only while running AND parked on a downhill slope...???

Vehicle in question is my girlfriend’s 2000 Jeep Grand Cherokee Limited, 4.7l V8 motor, about 150k miles, full time 4WD.

The other day while I warmed up the Jeep in my driveway for her I noticed a slow drip leak coming from the underside of the car…before she left (car warmed up for about 30 minutes as it was REALLY cold outside) there was a puddle of ATF (finger checked, pink in color) about the diameter of a large grapefruit under the front end of the vehicle.

The car was parked on a very steep downhill (my driveway, I live on a downhill slope). I checked the tranny dipstick after she got home and it was full.

Strange, I thought. I asked her to continually check for fluid under the Jeep when she parked it on a flat surface, her parking lot at work, and she’s saying there’s nothing.

The only time we noticed it is when it’s parked in my driveway and only while the vehicle is running.

What gives? Is there some forward seal that’s giving way? I haven’t crawled under the thing yet to look but I find the combination of leaking tranny fluid only while running and only while parked on a steep incline to be a bit weird.

What’s the Dope?

Sounds like the front seal (behind the Torque Converter).There should be an inspection cover on the bottom of the bell-housing where you could check.

My first guess would be the o ring on the dip stick tube. The fluid level in the front of the trans raises when you are on a hill. Also possible that a dust cover may be holding oil and tends to drain a bit when parked on a hill.

Where is the o-ring on the dipstick located?

A ot of cars have an O ring seal right on the tube where it pushes into the trans, not sure where it might be located on your car but just follow down the tube with a flashlight and you should be able to see easy enough if it is leaking or not.

I thought it only leaked when it’s running. Wouldn’t the tube leak as soon as it was parked on a hill whether it was running or not?

Most of the time yes, It might be a slight seal leak as you suggested but building up on a dust cover and when parked on a hill starts leaking.

if the front seal of the tranny is leaking ( behind the torque convertor ), that will be a tranny drop to have it inspected and replaced …

the o ring for the dip stick, well that at the end of the tube ( at where it meets up to the tranny ) and would need to be unbolts from the back of the engine ( or bell housing ) than pushing up on the tube ( to separate it from the transmission ). pull out or take off ( sometimes it stays in the hole or still on the tube ) and replace.

repeat the process in reverse installing the tube …

For a 14 year old car, I wouldn’t do anything except buy a bottle of fluid and make sure it’s topped up periodically.

You say the puddle was under the front of the vehicle? Like close to the grille or the front wheels?

I believe this truck uses ATF in the power steering too. I’m not totally sure how you’d get a leak there that only leaks when you’re pointed downhill, but maybe something like a leaking rack that only leaks when the suspension is loaded in just such a way would do it.

If you can catch it in the act it should be pretty easy to tell where it’s coming from.

Ah, I’ll have to check into that. I had no idea that the Jeep used ATF in the power steering. It is pretty far forward where it’s leaking…maybe about a foot back from the end of the grille, dead center under the vehicle.

Plus the fact that you described the fluid as “pink” instead of “vaguely reddish brown and burned-smelling” suggests to me fluid that’s spent the last decade and a half living the easy life in a power steering pump instead of a transmission. :slight_smile: