Blew smoke going uphill (scary)

97 country 4.0 auto 4x4

I posted this in the O/t as a rant but thought I would put it here to try and get some input.

On the way up the mountain roads I started pouring white/blue smoke from behind(not tailpipe).

It was a scary moment and made me glad I had the extinguisher within arms reach and not buried in the trunk under all the gear. It sucked because the XJ was performing brilliantly, no sign of any trouble at all. My temperature was right on the 210 line, good oil pressure and no sign of trouble when boom cloud of smoke. The smoke was gone before I could even slow down and pull over but it was clear it was coming from the exhaust where it crosses from one side to the other and it was wet. The bell housing was wet at the very top but not as high as the valve cover.

Today with it cool I was looking things over, all my fluids were fine except low on transmission fluid. I also had no signs of contamination of any fluids. The wettest spot is on the driver side bell housing right around/above the CPS. My ultragauge was showing a TC for the CPS, I don't have the number off hand but it was showing a faulty CPS. I removed the bell housing inspection cover and my flex plate is bone dry and no signs of fluid having drenched inside of the bell housing. I have some dried on junk but nothing looked wet inside from what little I could see. I can't see the vent tube going into the transmission but I know it is on the top but I thought the passenger side. I can see the end of the vent tube down low behind my transmission dipstick but I don't see signs of fluid having come out of it, it has some sort of cap on it but is dry around it.

Why I have a transmission fluid leak around/above the CPS doesn't make sense to me. Unless it is the vent out of the transmission and it just sprayed that direction? I have a new CPS ready to go in and will try to look for the vent source also while in there.

I've searched and found a lot of people with the same issue of blowing smoke when going uphill. I am worried it is the seal on the transmission but I can't confirm or not. It is also odd that it is wet Above the CPS though....

I drained/refilled the transmission and the fluid came out nice and red not burnt looking at all.

ive had a similar issue with oil from the rear main seal leaking on the crossover exhaust pipe. usually smokes for a few minutes until it burns off. it only happens when going up a steep hill.

Sounds like your auto trans overheated. Try shifting into 3rd when climbing steep grades (like the owners manual says) and you'll keep from doing that again. The aw4 has a vent hole on it and when the trans temp gets too high, the fluid expands and bumps out. I first learned about this eleven years ago driving my xj up the hills in central cali in overdrive. Happened to me once since then when I wasn't paying attention, but I always downshift when climbing now.

ECKSJAY said:

Sounds like your auto trans overheated. Try shifting into 3rd when climbing steep grades (like the owners manual says) and you'll keep from doing that again. The aw4 has a vent hole on it and when the trans temp gets too high, the fluid expands and bumps out. I first learned about this eleven years ago driving my xj up the hills in central cali in overdrive. Happened to me once since then when I wasn't paying attention, but I always downshift when climbing now.

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Yea I spaced on not shifting, again I never drive on that sorta hill I livei n a Flat valley. I am hoping it was just over heating and puking fluid and that it didn't blow a seal...

Is 3rd still ok when going 65ish? The speed on these roads are 65.

Yup...I concur. I did the same thing once pulling a hill with a light utility trailer. I remember now.

Yea, 3rd should be fine at 65 mph. Do you have a tach in the dash? You can keep an eye on that to know for sure.

Yea my tach works fine. I didn't notice any major shifting in and out of gear though going up the hills. It would kick down a gear at the bottom of the hill then shift back up a gear when I made it to the top. How it shifting manually into 3rd better?

Not arguing with anyone just trying to understand how it's working.

http://www.naxja.org/forum/showthread.php?t=1056883
This is also the same problem. I dont think its the trans overheating. Is your rear hatch covered with oil?

This happened to me as well.

I think that it has to do with torque convertor.

it was a simple transmission overheat. the vent tube runs right on top the bellhousing like you wrote. you probably did not hurt anything, but it is a good idea to now have the transmission fluid changed. burnt fluid distroys the transmission. you can have a full fluid flush, but many people just drain and add a couple times. this will get most of the burnt fluid out of the torque converter as each time it will mix with the new fluid added. i would drain the pan, then add to fill about three times. the third time droping the pan and either installing a new screen or cleaning the old one. (new is cheap and easy).

So now I am worried. I was driving today on a flat highway going 65 for maybe 15 minutes when I had smoke billow out again. I let off the gas and start heading off the highway and the smoke went right away. I got off the highway and checked things out and again the exhaust was wet with fluid.

I had no sign of over heating, I was going a steady 65 not passing or anything, I didn't feel the transmission shift at all before the smoke.

Anything else to check as the source/cause of fluid puking out?

Today with it cool I was looking things over, all my fluids were fine except low on transmission fluid.

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Hopefully it's a stupid question, but you're checking your ATF level warmed up, idling in neutral, right? Haven't overfilled or anything silly like that?

hubs97xj said:

Hopefully it's a stupid question, but you're checking your ATF level warmed up, idling in neutral, right? Haven't overfilled or anything silly like that?

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Yes, checking in my level garage after driving it a while, cycling all the gears and idling in neutral. I just drained/refilled over the weekend and the fluid is not overfilled.

Just to update this.

I was talking with a buddy and he said if transmission fluid is over flowing to check the dipstick. I said that I had checked and it was dry, he however mentioned it being a 2 piece dipstick tube... I checked today and sure enough, the 2 pieces had a large gap between them. Some where along the lines they had separated!

There was a lot of grim built up on both sides of the dipstick tube so I don't think it was very recent that they split apart. Now with that large of a gap my dipstick was not reaching into the pan and giving me a false reading. I was adding way more fluid to make up for that gap leaving my transmission over full.

I drained the pan again today(fluid looked pristine still) and I added back 1 1/2 quarts and was past the Fill line. I stopped there and plan to fill/check it with it running tomorrow but my guess is I won't add more than 2 quarts total for this drain/fill. Usually when I drain/fill I add 3-4 quarts.

I also checked the inside of the bell housing for signs of the transmission front seal leaking. I took a clean towel and ran it all around the inside of the bell housing. It came back out dry/dusty with a lot of little debris on it. I have to imagine if the front seal was leaking fluid would fill the bottom of that housing and flush out any dry debris. The opening at the bottom inspection cover is big enough to let all that junk flush out if fluid was in there. My flywheel also had a dry dust layer on it which would again in my mind be washed away with a fluid leak in there and the rotation flinging it all around.

My hope is that the fluid was puking from the dipstick and getting to the exhaust causing the smoke. The other possibility is the rear main seal which has a tiny drip but maybe at high rpm/load it really dumps fluids and I in-fact had 2 leaks when I was blowing smoke.

Any input with the new findings, I am trying to cover everything without dumping money at parts, I have really gotten into diagnosing rather than just fixing ; ) .

sounds like you have it figured out with the dipstick tube. i would now fill it properly and drive it to make sure it is all good

and 3rd on the highway at 65+ is not a problem for doing hills, it is MUCH preferred over letting the TC slip.

I added a total of 2 1/2 quarts to get me to the full line while at operating temperature in neutral. Then I went for a 2 hour flat highway cruise today, no sign of smoke or oil on my back window so far so good. Next test is the mountains again ha. I hate the thought of something going wrong being stranded so far from home but if it's gonna happen it's gonna happen there.

Just because I happened to see my old thread and can update all is well. I happened to be under the XJ the other day and saw no sign of oil anywhere. I am now satisfied the RMS was leaking and hitting the exhaust where it crosses over. That section of exhaust was always black looking. Now it is just rusty like the rest with no sign of oil hitting it any time recently. Also, no problem with the transmission dipstick tube or transmission fluid puking out any where.

Here I am again years later with the same symptoms on the same stretch of highway, only now with more details. I went for a drive up the same hill where this issue began and I started blowing smoke really bad out of the back. I pulled over and saw transmission fluid covering the underside of the XJ.

Now, leading up to this I had recently done a drain/refill and installed a transmission temp gauge, remote cooler, remote filter and then a second drain refill. I like to think that I am certain the level was correct checking the fluid after driving while Hot in neutral with the engine running I was at the correct level.

On the road when it blew fluid / smoke out I stopped to check and there was no fluid on the dipstick. I added 2 quarts and limped back home stopping to add another 1 quart before making it home. The fluid was seemingly coming from the bell housing, not the vent or any of the cooler lines but I am not 100% until I get it in the garage for a better look.

My trans temp gauge never seemed to indicate any great temp increase which worries me as I should have seen some heat build up while climbing the steep hills going 65mph. At the same time, my engine temp stayed right on the line with no great increase either, everything was running great. I initially hoped that it was just over full with trans fluid and was expanding and puking it out but the amount I lost makes me think thats not the case. Being over full would cause expansion and eventually level itself off?

Things of note. I was shifting down to 3rd for the hills and the rpm were at about 3k during the hardest climbs. I stopped at a walmart for fluid and let things cool down and there was never a puddle of trans fluid under the XJ or signs of an active leak. Once I got off the highway onto surface roads, the 30 minute stop and go traffic showed no signs of smoke. The mass amount of fluid that puked out when I stopped to check the first time really scared me though, the whole under side was soaked and seeing a dry dipstick.

I am leaning more towards front transmission seals now unless someone thinks other wise? If it were over full and was a case of fluid heat expansion would it spew that much fluid out or stop once the excess had blown out? Also I am finding it hard to suspect transmission over heating but no sign of it on my gauge, not saying the gauge didn't have a mishap or something but all signs are pointing towards it not being an over heating issue so far I think.

It's all very frustrating I will say that, having everything run so well no signs of transmission fluid leaking for years then this same situation again on the same road. I was on the way to a nice remote lake for a weekend of fishing too and had to turn for home about halfway there :bawl: . Now the thought of having to pull the trans to get at these seals.... ugh

I will make it up this stretch of road yet though, its now my mission!

I got the XJ in the garage and looked over things a bit more, no sign of leaks anywhere other than the bell housing.

I talked to a friend and his first thought was not the seals but the trans pump, his concern was that it was only spewing fluid during the steep hills when the pump was being pushed hardest. I figured the pump was pushing hardest and then causing the seals to fail meaning the pump was just fine and its all pointing towards the seals...

I am also thinking maybe it was just over filled and spewed out when it got hot even though it sure seemed like it was at the correct leve. The last two times I drained / refilled I got 3.5 quarts out and put that back in.

I am going in circles on pulling the trans and doing the seals or draining some fluid and confirming the fluid level and trying it again. Trying again just worries me because the only time I get the leak it seems is when I push the XJ hard up mountain roads which is a bad place to have problems.

Have you checked that the vent tube on top of the transmission is open and allowing air to vent. I can't see how it can be a seal if it's not leaking consistently. When you climb, does it feel like it's slipping or does it feel locked in it's gear?

Also, all the seals external to the transmission are not under any hydraulic pressure. I don't think the pump has anything to do with the problem. But the throttle valve cable does regulate line pressure. Is that set correctly?