richv Posted October 21, 2008 Share Posted October 21, 2008 This has been driving me crazy, so I decided to post here to see if anybody could help figure this out. On October 4, I drove my stock 1992 Jeep Comanche with 4.0/AW4 about 200 miles to pick up an old Chevy coupe body. During the week before this, I had some issues with the "check engine" light and battery light coming on periodically. On Friday the 3rd I had the charging system tested and everything looked good, and neither warning light came on after that. Of course, on the way to pick up the Chevy on the 4th, the check engine light came on. The battery light would go on and off periodically. Right after I left to head home, both lights came on and stayed on. About halfway home, everything died - the truck had been running on battery power only and the battery died. My wonderful wife got a new battery and brought it to me. I installed it, hoping it would get me home, which it did. OK, here's the strange leak part of the story. About 30 miles from home, my wife (following behind me) called my cell phone and told me that my truck started blowing smoke out the back. It was starting to get dark, everything was still working, so I kept going so I could get home before I had to turn the lights on. Upon returning home, I had transmission fluid dripping from the whole underside of the truck, more so on the passenger side, from about where the cooler lines are attached to the transmission back. The smoke was the result of the fluid burning on the exhaust. I replaced the alternator the following day and cleaned everything up, then went to try to find the tranny leak. It didn't leak anymore. I've been driving it every day since then, about 30 miles a day, and it has not leaked at all. I'm wondering if it had anything to do with the load in the back of the truck, probably 600 pounds or so. Any ideas? I initially suspected the tranny cooler lines, but they're OK. Sorry for the long story! Link to comment Share on other sites More sharing options...
oldjeep Posted October 21, 2008 Share Posted October 21, 2008 What does the fluid look like - pink or semi burned? If you were loading it up sometimes the fluid will start puking out the breather or around the TC seal, especially if you are having to give it so much gas to maintain speed that the TC is not locking up at highway speeds. Link to comment Share on other sites More sharing options...
richv Posted October 21, 2008 Author Share Posted October 21, 2008 The fluid was semi-burned. The MJ used to be a plow truck, so even though it only has 70,000 miles on it, the drivetrain has been worked hard. I need to get some new fluid in there and check things out. It shifts fine, though. Link to comment Share on other sites More sharing options...
Wildman Posted October 22, 2008 Share Posted October 22, 2008 You didn't say that your checked your tranny fluid level after you got home........I would think you did. With the long drive you had, and "pushing" it with the extra weight, there's a good chance that your were over working the tranny. On the right side of the tranny / engine, there is a breather for the transmission, it's mounted on one of the tranny/engine bolts, up high, right near the tranny dip stick tube, the fluid could have expanded and started foaming and escaping out of the breather, and like you said, dripping down on the exhaust, and burning off. Even with the "low" mileage you have, 70K, you should really do a fluid change, like every 30K miles, drain the fluid, and get a filter and pan gasket, and that should help preserve the transmission for some time. And if the fluid is "semi-burned" I wouldn't wait too long to change it. The AW4 is a stout tranny, but yes, they do fail, and hopefully your is not that far gone........yet. Link to comment Share on other sites More sharing options...
richv Posted October 22, 2008 Author Share Posted October 22, 2008 Thanks Wildman. I did check the fluid when I got home; it was just shy of a quart low. I'm going to change the fluid and filter this weekend. Hey, at least now the bottom of my truck is coated well for a long Wisconsin winter of road salt! :) Link to comment Share on other sites More sharing options...
Wildman Posted October 22, 2008 Share Posted October 22, 2008 :teehee: Yea.......now if you do that every 6 months......your MJ will last another 20 years :D Oh........I came across This if you need any pointers on that job ;) Link to comment Share on other sites More sharing options...
pingpong Posted October 22, 2008 Share Posted October 22, 2008 I think you probrably "boiled" your tranny fluid. At least that is what it sounds like. Once that stuff gets hot and starts to boil it finds a way out the trans... It happens all the time at work with the fork trucks... especialy considering that the hydraulics are ran off the same fluid resivoir as the trans Link to comment Share on other sites More sharing options...
richv Posted October 25, 2008 Author Share Posted October 25, 2008 Thanks for all the info. Tomorrow I'm going to replace the fluid and the filter. Link to comment Share on other sites More sharing options...
oldjeep Posted October 25, 2008 Share Posted October 25, 2008 Thanks for all the info. Tomorrow I'm going to replace the fluid and the filter. How are you planning on doing that? You either need to build your own fluid replacer or take it in. Dropping the pan only gets about 1/3 of the fluid. Link to comment Share on other sites More sharing options...
richv Posted October 25, 2008 Author Share Posted October 25, 2008 I had it flushed. Link to comment Share on other sites More sharing options...
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