View Full Version : 88 XJ Trans Leak-- Clueless--Need Help

October 14th, 2006, 22:14
Hello all. I am in need of some help in diagnosing the root of a transmission leak. I have an 88 XJ with an auto trans with the 4.0. The Jeep operates fine with no trans fluid leaking if running short trips. However, if I drive over about 15 minutes the fluid starts leaking real bad hitting the exhaust pipe smoking all over the place. I have taking it to a few tranmission shops, but the can't diagnose it and state it doesn't leak for them on their test drives. this is because they aren't driving it long enough. I am clueless about where the leak is coming from. I have owned this Jeep for 6 years now, its been re-painted and is in great shape. I would love to get this problem resolved so that I can enjoy the Jeep this winter. Does anybody have any input regarding this problem. Any repsonse if greatly appreciated.

October 15th, 2006, 01:51
Check where the tranny cooler lines go in and out of the tranny. They used this stupid plastic clip to hold the lines in. My 88 had a leak where the plastic clip had worn out and broken part-way.

October 15th, 2006, 01:58
If it is your transmission cooler line connection, that plastic tab is part of a "quick disconnect repair kit", a set of "O" rings on a spacer plug, same as the fuel line connections. To disconnect, just squeeze the plastic tabs and pull on the male side of the connected lines. Don't try to reuse them once the line is disconnected. Also easy to leave behind "O" rings or spacers when replacing them. Find the "kit" at the dealership, anywhere from $12-24.

October 15th, 2006, 07:27
By now, it's likely pretty greasy underneath. You need to get some cleaner and thoroughly wash everything in the area of the suspected leak. Then drive around and see if you can detect the fresh oil.

October 15th, 2006, 07:34
I have the Same deal going on with my 98. The lines are on the passenger side of the transmission correct? Both of those lines are for the Tranny, or one tranny, one engine oil? Would I need to train the fluid to change out the tubes, or no?

October 15th, 2006, 17:18
Thank you everybody for your response. I deeply appreciate the assistance. This week I am going to head out with some Simple Green and clean off that area and take a good look. I will research the coolant line clips as mentioned. I really hope that this is the problem. Again, thanks for the input.

October 15th, 2006, 17:34
I have the Same deal going on with my 98. The lines are on the passenger side of the transmission correct? Both of those lines are for the Tranny, or one tranny, one engine oil? Would I need to train the fluid to change out the tubes, or no?

Both are for the tranny. One(the upper) goes from the tranny to the cooler in the radiator, the lower is the return line from the radiator. If you have a factory secondary cooler, the fluid runs from the tranny to the radiator to the cooler, then back to the tranny.

You would only need to drain the one you are working on. It will run out on you anyway.

October 18th, 2006, 02:03
So I'm still not sure what is leaking. I went under my jeep today, and cleaned it up best I could.

I took pics, and found a crimp in both lines. There is no visible leak, but I'm sure there is somewhere in there. Would it be safe to zip tie a rag or something below the lines so I can see if that is what is leaking? Would the rag catch fire under such heat? I can never diagnose the problem, because it always burns fumes when i'm on the road.

The lines are super long too. Replacing just one looks like alot of work. Can I just cut the two crimps out and add a patched piece of line in there?

October 18th, 2006, 03:30
your tranny is overheating and spewing out the dipstick tube i bet. it's overheating because not enough fluid(or any) is getting to your cooler, or it is building up fluid and squirting out the front seal. try to replace the whole line if you can, if not you may be able to cut the crimp out and double flare both sides, get some SS braided line rated for transfluid. be sure if you do go to hose it is rated for trans fluid, it needs to not only withstand oil but also extreme heat and pressure. be sure to get this fixed as soon as possible, the aw4 is a great trans but most trans faluire is caused by heat. also figure out why it got crimped, looks like CA mount on axle smacked it? maybe even the pan? is that even possible? maybe you got a branch or rock jabbed in there? and no tranny shop found that???!!!!!!!!!! go back and slap all of them across the face with a rubber chicken, they are idiots.
good luck, Jeremy

October 18th, 2006, 09:10
You need to check either your motor mounts or front bumpstops & see which is allowing your control arm to hit your oil pan/tranny line; probably you don't have enough bumpstop in the front.

Yes, you can cut, flare & clamp on a section or 3/8" tranny hose or power steering hose (whichever your local auto parts store has in stock cheaper)

You need to fix this problem right away - you are overheating your tranny & possibly causing damage by driving it, if it is not fixed soon, your tranny will fail from heat. Your temperature guage reads in the radiator; so without tranny fluid getting there you'd never even know it's overheating...

October 18th, 2006, 11:16
Looks familiar to me. My son pinched his line like that because he didn't have a bump stop on the right side and the UCA mount got the line.

Replacing both lines is not that difficult. Hardest part is getting the quick-disconnect fittings to let loose. Lines are available at NAPA, and not too expensive if I remember right.

October 18th, 2006, 15:04
I replaced both quick connects on my tranny side due to cost invovled with buying replacement lines from the stealership.

If you unscrew the hexagon housing where the quick connects sit, it is standard flare threads.

October 18th, 2006, 15:39
So I got some tubing to replace the crimps, but can't remove short sections of pipe easily. What should I use? A dremel?

October 18th, 2006, 15:48
I used a mini tubing cutter. But a dremel would work.

Blaine B.
October 18th, 2006, 16:49
Mine would do that when overfilled, out the vent at the top (when highway driving), onto the exhaust. I had to flush it anyway, so after that I filled it to the correct level, and it hasn't happened since.

October 19th, 2006, 06:23
I wouldn't try to patch those lines. Suggest going to a bone yard for the lines, then dealer for the reapir line kit to hook up the quick connects. Tranny fluid WILL catch on fire at a lower temp than motor oil, so don't use a rag. Good luck.

October 19th, 2006, 09:51
So I got some tubing to replace the crimps, but can't remove short sections of pipe easily. What should I use? A dremel?

Next to the flare tool at the parts store should be a "brake line cutter" tool. Should be around $5. They look like this:

October 19th, 2006, 16:11
The lines were too close to alot of stuff, so the circular pipe cutter wouldn't work. I patched the lines. When the car was off, the dipstick showed full level of transfluid, but when i turned the car on and let the engine run, then off; the dipstick showed nearly empty. I filled to adequate level, and now it runs great. I still smell burning, and I think it is either left over fluid still on the exhaust, or my quick connects are bad from so much pressure building up in there an allowing fluid to seep out.

The Jeep runs great though, and I'll keep checking up on it, but for now it's good.