High-Speed ATF Leak, '98 Jeep Cherokee

[Fleetmon]

I noticed this once before; hot weather, high-speed driving (well, 70 MPH which is pretty high speed for a Cherokee! LOL!) caused trans fluid to blow out....maybe from a vent up on top of the trans? I haven't had a chance to look at it yet but it appears it blew some out.....idling last night, I didn't notice any active drips or leaks but evidence shows it dripped some after parking and I could smell it....definitely ATF and a cursory look shows it may be coming from the top of the trans.

Has anyone experienced this before? The last time it occurred, I thought maybe she had driven it in 4-wheel drive (although she said she hadn't) and chalked it up to that possibility but then it happened to me yesterday.

 

[eljefino]

Torque converter clutch working right?

 

[Fleetmon]

As far as I can tell everything is working fine.....no trans slipping, trans is shifting fine, RPM at 70 MPH is right around 2200 where it's always been, and fuel mileage (17 MPG) is staying the same. I don't notice anything differently except this fluid loss.

I mentioned it to someone else who has a similar Cherokee and he said his started doing it and shortly afterwards the trans failed completely but he didn't know exactly what failed....said he sold it as is when that happened.

Nothing feels catastrophic or that any failure is impending and it drives normally although she has complained that it "clunks" into gear from reverse to drive. I haven't noticed any peculiar clunks other than what it always appeared to do.

 

[Zaedock]

Check the vent and make sure the small inline filter is not clogged. Here is a good modification to extend the breather into the engine compartment, which is a much cleaner environment for a trans vent.

AW4 vent mod

 

[Zaedock]

The clunk into gear is possibly a ujoint in the rear driveshaft.

 

[SwampSurvivor]

Have you jumped it or anything crazy recently? It's not uncommon for the control arm on the right side to crush the transmission line. Other than that, look into the vent mod.

Does the clunk happen when you come to a complete stop or take off? If so - grease the slip yoke (there's a few guides on it).

 

[Fleetmon]

Good info Zaedock....thank you. It appears the "leak" is more concentrated on the right side of the trans based on a quick look underneath with a flashlight.

U-joints feel tight but I'll get a better look at them this weekend.

Thanks again....all great stuff!!!

 

[Fleetmon]

I don't think she's been jumping anything or doing anything crazy....lol! It's rare when it gets out on the open road but I took it to work the other day which is a 70 mile interstate ride at speeds of 70 MPH and higher.....and that's when I noticed it. Up until this time, it's been driven regularly around town with no issues and I just checked the trans fluid level a week or so ago and it was good. I replaced the fuel tank and rear shocks about one month ago and didn't notice any leaks or anything that would have caused me concern while under it (also looked at the u-joints then).

 

[jeepman3071]

Did you check the fluid with the Jeep up to temp? I had a similar issue shortly after buying mine. Turned out the used car dealer I bought it from overfilled the trans, and when the fluid warmed up and expanded it was going out the vent.

Does the fluid appear burnt?

 

[wsar10]

Over the years of many JEEPS, all my tranny fluid leaks resulted in a cooler line being the culprit.

 

[Fleetmon]

no burnt fluid and the trans was checked at operating temp (by coolant temp gauge after a 45 minute errand).

I don't think I have a leaking line since it should be leaking all of the time....no sign of an active leak when started and it still has plenty of oil in it.

I think the breather is probably the culprit....the Jeep parks in the same garage space all of the time so a leak would be pretty noticable and it has done this twice now, both times in hot weather and after a spirited drive, i.e. interstate driving.

When it happened it apparently didn't blow any oil out on the way into work since my parking spot doesn't show any signs of it but the drive home (and at a much higher ambient temperature) seemed to have brought it on.

Also, my wife just took it out (unbeknowst to me) and said she noticed no problems with it, no odor, and she doesn't see any leaks underneath but it was just a local, maybe ten mile, drive.