Need help finding a leak

[Mower2339]

To start I would like to say that I have searched this forum and many others with no success, and finally decided to post here in hopes that someone has an idea of where the leak I have could possibly be coming from. I recently purchased a 2003 Rubicon, which is the Jeep I have wanted for a very long time. It has a small lift, set up right and for the most part drives like a brand new Jeep. After getting it home I have noticed a funny smell, likely after going 80mph down the freeway what smells like gear oil must have got onto the exhaust. Anyways so I crawl under the Jeep, inspect the transfer case, the transmission, ect. And noticed there is a gold colored oil, I'm nearly 100% certain it's gear oil by the smell, that has accumulated enough to drip off the rear portion of the skid plate. After further inspection I noticed that it has flipped up all over the tub above the rear driveline. My question is where could this be coming from as from mid skid plate forward is completely dry, nothing on top or on any side of the transmission, which to my understanding is the only thing aside from the diffs that contain gear oil. The output shaft on the Transfer case is wet, but to my understanding this should be ATF+4 and red, not gold colored stinky gear oil. My next step would be to drain and refill both transmission and transfer case, as I'm wondering if the retards at the dealership (used car), might have put gear oil in my transfer case. It is a Rubicon, so I'm wondering if by any chance there is a component that could be bad that uses gear oil in that area. There is a solenoid looking thing on the driver's side part of the rear end of the skid plate, and it has this oil on it, but im unsure why, and am not completely sure what that is. I'm assuming it might have something to do with the lockers. Any help would be appreciated. Also, I did purchase a bottle of Penzoil Synchromesh as initially the smell and location pointed to the manual trans leaking, but haven't pulled the plugs to check yet. Any recommendations on fluids? Trans case, Transmission, front and rear diffs? The dealership had replaced all seals, including rear main, and the Carfax hx report said that it's recently had diff fluids changed. I hate to replace it all if it's just been done, but don't know what else to do. I also wonder if they spilled a bunch when doing this and it's just simply been blowing off the skid plate, hitting the rear driveline and being flipped everywhere. Thanks in advance for any help in pointing me where to look. I can see no active dripping, just gear oil from the rear portion of the skid plate, output shaft, front of rear driveline, and above this area on the tub.

 

[IPerkWVU]

Can’t help with your main problem but the solenoids you described are your air locker pumps. Gear oil wouldn’t be coming from there.

 

[JEEPCJTJ]

At Because of where you have this leak I'd be surprised if the transfer case wasn't doing the leaking and I'd also be surprised if someone didn't put gear lube in it either accidentally or maybe on purpose.

You should be able to tell what's in there buy just draining a couple drops.

 

[Mower2339]

Can’t help with your main problem but the solenoids you described are your air locker pumps. Gear oil wouldn’t be coming from there.

Thanks, I figured they had something to do with the lockers, just wasn't 100% sure.

 

[Mower2339]

At Because of where you have this leak I'd be surprised if the transfer case wasn't doing the leaking and I'd also be surprised if someone didn't put gear lube in it either accidentally or maybe on purpose.

You should be able to tell what's in there buy just draining a couple drops.

I intend to do so as part of the process in figuring this out. The dealership that I bought this from seemed a bit shady. I picked it up for under 10 grand with 103k miles though, and other than this issue (which could be that someone just spilled a bunch on the skid plate while servicing it) it honestly drives like a brand new Jeep, better actually that my old '13 JKUR. The OME lift with all the right track bars, mounts, control arms, ect. seems to be in a league of their own when it comes to lift kits. It honestly rides so good, zero rattles, zero slop in the steering, it honestly feels like a brand new vehicle. So with the cheap price tag, the OME complete set up lift, oh it also came with a Warn 9000lb winch, warn front and rear bumpers. I'll figure this leak out one way or another, it's just so damn cold outside, I'll have to wait until I can take it to my dad's shop.

 

[T Crawford]

Pop the fill hole on the diffs and stick you finger in and pull it out and see what it looks like, I usually redo all my own fluids on a used car so I know what’s in there and when it was put there, check your brakes and you’re ebrake pads, and enjoy the rig, any photos?

 

[Mower2339]

Pop the fill hole on the diffs and stick you finger in and pull it out and see what it looks like, I usually redo all my own fluids on a used car so I know what’s in there and when it was put there, check your brakes and you’re ebrake pads, and enjoy the rig, any photos?

Yea, I'm new to the forum, I'll take some pics tomorrow, why the brakes? The E-Brake doesn't work that well, or at all really, but it wouldn't have anything to do with the oil right? Again, I do some mechanic stuff, but do not claim at all to be a professional. The biggest job I've done is replaced the clutch in my '99 Cummins. I have replaced the clutch in a friend's TJ Sport as well, but mostly just ball joints, bearings, plugs, fuel pumps, ect. Basic little jobs that I refuse to pay for. Here is a pic of the Jeep, I'll take some underneath around where the fluid is located tomorrow when it's light.

 

[Paranoid057]

I suspect they put in gear oil in the TC as well, would be simple enough to check via popping out the fill plug and sticking a finger in.

 

[Mower2339]

I suspect they put in gear oil in the TC as well, would be simple enough to check via popping out the fill plug and sticking a finger in.

I will check first thing tomorrow and update. The more I think about it, this has to be the case as most of the oil slung around is right at the output shaft on the TC. I have got under there and looked on top of the trans to make sure it wasn't leaking from the top where the stick goes down in, and nothing, in fact the entire transmission is dry, not a smidge of 90w anywhere. And the rear part of the driveline may have a little 90w there, but nothing like the front of it near the output shaft on the TC, also it's directly above the front portion of the rear driveline that the 90W is slung all over the tub. It does seem oilier towards the driver's side of the skid plate, but that may be coincidence. It looks like there could be a small drip on the fixed yoke, I wipe it off, smells like 90w. I hope that if this is the case, that the 90w hasn't damaged my fancy Rubicon 4:1 transfer case, and also that the seal isn't hard to fix. I'm assuming I refill it with ATF+4?

 

[Vinman]

Just thinking out loud here but I wonder if it’s possible for the diff to pressurize due to a plugged vent line and push gear oil out through the air locker line. That may explain the gear oil around the compressors.
Never heard of it happening before.

 

[Goatman]

It could just be stupid people doing stupid things. Many "experts" know the transfer case gets gear lube. No need to check the book. They are also likely to just pump it all over and overfill the case and then stuff the plug back in. This could account for the oil all over the skid. Once this mystery is solved I would recommend you change out every fluid in the vehicle. Who knows what else these "expert" "mechanics" might have done. This includes p/s and a complete flush of the brakes. Tjs tend to get glumpy shit in the brake lines more than other vehicles. I'm guessing it's the choice of material in the rubber flex hoses and years of different people adding whatever brake fluid they have laying around.

Good luck! Welcome to the Forum

 

[Mower2339]

Just thinking out loud here but I wonder if it’s possible for the diff to pressurize due to a plugged vent line and push gear oil out through the air locker line. That may explain the gear oil around the compressors.
Never heard of it happening before.

Could that happen? Maybe too much fluid in the diff? Theoretically speaking I mean.

 

[Mower2339]

It could just be stupid people doing stupid things. Many "experts" know the transfer case gets gear lube. No need to check the book. They are also likely to just pump it all over and overfill the case and then stuff the plug back in. This could account for the oil all over the skid. Once this mystery is solved I would recommend you change out every fluid in the vehicle. Who knows what else these "expert" "mechanics" might have done. This includes p/s and a complete flush of the brakes. Tjs tend to get glumpy shit in the brake lines more than other vehicles. I'm guessing it's the choice of material in the rubber flex hoses and years of different people adding whatever brake fluid they have laying around.

Good luck! Welcome to the Forum

Thank you for the advise, and I'm thrilled to be a part of the forum that I have used so many times over the years! Maybe I'll be able to return the favor of helping someone figure something out one day. As I stated in my description: "This addiction started when I traded a decked out '07 Yamaha Grizzly 700 for a '94 YJ Wrangler. 5 Jeeps, 1 Landrover, and a GMC Yukon later I finally have my Mona Lisa....An '03 TJ Rubicon that is set up nearly exactly the way I want it......It could be white instead of black". Anyways, thank you, I'll get this leak figured out, 1st step is seeing what was put in my TC. This is a perfect example of why I do ALL of my own maintenance.

 

[Mower2339]

So I had a few minutes to crawl under the Jeep tonight (albeit it's freezing cold, even in my garage). Anyways I couldn't get the drain plug out of the transfer case, I bought some atf+4 pulled the fill plug, dipped a strand of white thread in there and to my surprise it came out with red fluid on it. Upon further inspection of the tub (above the rear driveline) it appears to be ATF that was leaking.......or blowing off the skid plate. I'm starting to think this leak might not be a leak at all rather a messy previous service job in which they let old trans fluid drain all over the skid plate, filled with new, threw the plug in and called it a day. Again I couldn't remove the drain plug, I started to round off the 10mm hex plug and decided to stop before I completely strip it out. I did get the fill plug out and decided to make sure it was topped off. It took less than 1/4 quart of ATF before it was leaking back out. This is further evidence to me that it might not be a leak, but rather a fluid covered skid plate that blows onto my driveline and flips all over everything. The locker compressors are still suspiciously covered in oil, seems to have more than anywhere else under there. Now my next job will be to watch it, see if more oil accumulates there. I wiped it fairly clean, enough at least to tell if it's leaking more in the future. Also I now need to drop the skid plate, and carefully remove and replace the damn trans drain plug that I started to strip. My thoughts are take it to my Dad's shop, get it lifted up to where I can better work under there, drop at least the rear portion of the skid plate, maybe pound an 11mm Allen key in there and use a little heat to get it out and then replace it. I'd like to replace it with something easier to remove in the future, possibly a hex head bolt. I'll update this as I find any new info. Oh and while I was under there I noticed a hex head bolt about 3.5-4" long maybe a 14mm head on it just laying on the skid plate. I looked for an empty hole, but didn't see one.

 

[Mower2339]

So just in case anyone in the future runs across this problem I want to say that I ended up replacing the rear output shaft seal on the transfer case and it fixed the leak. Also when I drained the transfer case it looked as if the previous owner had put gear oil and ATF in there. That was the main reason I doubted it to be the rear output shaft, as I figured it would be ATF slung all over the underside of my tub, my exhaust, and the skid plate. Anyways I replaced the seal on the output shaft, drained and refilled the TC and now all seems to be well. Not a single drop of fluid on the skid now, which I cleaned pretty thoroughly while it was off the Jeep. For any who might face this problem in the future I will say it is a pretty easy repair, the seal was like $20 or something, and it took all of an hour, maybe hour and a half to do. Oh also I replaced the fluid in my manual trans that day as well and will say to any who are debating putting the Redline MT fluid in.......DO IT! YOU WILL LOVE LOVE LOVE THE WAY IT SHIFTS, SOUNDS, AND ALL OF THE ABOVE. My trans went from being sticky, hard to get into 2nd, and extremely loud when going down the road, to going though all gears like butter, and being virtually silent when going down the road!!!!! It's miracle fluid!!!!!

 

[Goatman]

I'm very glad you got it figured out. And a cheap fix to boot!
Another tip for Rubicon owners is when you have that skid off make a bracket to mount the locker pumps to. Drill and tap a couple of holes and mount it to the frame separately. That way when you need to pull the skid next time you won't have all the locker pumps and wires to deal with.
It'll be worth it the first time you pull the skid and don't have to fight all the locker parts. I would try and leave that 1 skid bolt on the frame and try and pivot the skid, trying to reach up and over the skid just to save me from dealing with disrupting the pumps and wire harness.

 

[Chris]

Thanks for reporting back, I'm always happy to read about a happy ending.

 

[Mower2339]

I'm very glad you got it figured out. And a cheap fix to boot!
Another tip for Rubicon owners is when you have that skid off make a bracket to mount the locker pumps to. Drill and tap a couple of holes and mount it to the frame separately. That way when you need to pull the skid next time you won't have all the locker pumps and wires to deal with.
It'll be worth it the first time you pull the skid and don't have to fight all the locker parts. I would try and leave that 1 skid bolt on the frame and try and pivot the skid, trying to reach up and over the skid just to save me from dealing with disrupting the pumps and wire harness.

That is a good idea, I actually thought that the locker pumps had been moved to the skid plate. It didn't look like a factory place for them to be mounted. They have just the 4 bolts that are tapped into the skid plate correct? The threads that are tapped into my skid plate are all stripped out so I can pretty much turn most of them out by hand. I do know that they got covered in oil from this leak, they looked hammered. I will look at moving them to the frame, as the skid doesn't seem like a great place for them anyways. Does everyone else's lockers take a few tries to go in? Mine sometimes go in the first press of the button and other times they flash, go off, and take a few additional tries before they go in. They have never not went in, and always seem to come out just fine, just curious if it's somewhat normal for them to be a little finicky?