OK, brand new engine in Jeep, reman with warranty. After breaking in the engine, I hooked up a small trailer, 4X6 enclosed, and loaded up the jeep. I was pulling fine for about 200 miles, when I hit a good size hill. At the top of the hill I started to loose fluid and smoke. I quickly pulled over and it is transmission fluid I am loosing. I had replaced transmission fluid right before the new engine. I am guessing a blew a seal, but I don't know. Any thoughts? I am going to go buy what I can and pull it apart to see what is wrong. The pan looks fine. It looks like it is leaking somewhere around the torque converter. I have a 2000 Jeep Cherokee XJ 4.0. Thank you for the help.

Nate

 

Just happened to me, ended up being the pump seal. Until you pull it and look at it it'll be hard to tell what seal. I overheated the trans in the mountains and that's what took out the seal.

 

Could I have just overflowed out the vent? I don't have the extra tranny cooler on it. Also, I didn't lose all the fluid, just a little. Once I pulled over, it stopped leaking. I am going to head down to where I parked the jeep right now, add some fluid and drive around to see if it leaks again. The fluid still looked good too. It didn't look burnt or smell burnt.

 

It's possible. After that happened to me I cleaned the entire underside the next day and drove it around to make sure it was leaking and where. A good 20min cruise should give you a good idea. My leak was reaaaally slow until it warmed up. Get up there with a flashlight and check around. I had to take my bell housing cover off to really get a good idea.

 

If you're going to be towing ANYTHING with an auto trans, buy and install a trans oil cooler. Jeeps with the towing package came with one, so you should be able to get OEM spec easily

 

U said u replaced the engine. Did u have the trans out ? OR did you leave the trans in and try to bolt the motor to it. I've seen on some engine pulls some leave the trans in and try to bolt the motor to it - alot of pressure gets put on the converter that way possibly damaging the seal and bushing .

Dis u do anything to the trans when the engine was out - reseal the outside parts that u could ?

U have to really find out where the leak is coming from- does the AW4 have a breather on it - is it clogged ? If the vent was clogged if it has one -I've seen them puke right oit the dipstick tube.

 

OK, just drove it 30 minutes, all up hill, and nothing leaking. Still, engine running cool, Jeep is empty now, no trailer, but the transmission fluid is reading a little high. I didn't check the transmission before driving because I just had it serviced. I checked after 15 miles, then 20 miles, and then 30 miles, and it still reads a little high on the dip stick. They could have overfilled and I was leaking out the breather or tube. Or, the trailer was back heavy, is it possible that the trailer, while going up hill, pulled the seal apart temporarily? I bought an aftermarket cooler to install also. Any tips on installing that? Should I stress the transmission to see the leak? What does it take to remove the bell housing?

Also, when we installed the engine, we left the transmission in, also, we did not replace the front seal, we forgot. I bought the part and everything, but after we had the engine all installed, we noticed the pump seal sitting there. The old one wasn't leaking in the first place, but meant to change it out. I have another couple hundred miles of towing I need to do before getting back home. Any thoughts?

 

Get a factory service manual and get that cooler installed.

 

Yes, I am installing cooler and temp gauge and then driving home. I still fear the pump seal is leaking, but I won't know for sure until I start towing the trailer again. With the temp gauge, I can watch for high temps and pull over when I have to cool down...I hope. My brand new engine is now covered in tranny fluid. If it ain't leaking, it ain't a jeep I guess.