Bad oil leak while driving and then nothing?

I was traveling up a pretty steep lengthy grade in my 98 4x4 XJ Sport on the freeway today at about 70 mph for several minutes running just over 3000 rpm in 3rd up the hill because I have a lift and 31" tires. At the top of the grade the road flattened out a bit and I dropped it into drive. I drove for several miles when I noticed what I thought was dust blowing up behind me. As I continued down the road the cloud got a little bigger until I realized it was smoke! I started moving to the side of the road and it was smoking really bad, at one point there was so much I started to worry it might be a fire. When I pulled over and got out I saw a pretty fair amount of oil dripping down from the drive train onto the exhaust and ground which was causing the smoke. I shut the motor off and continued for several minutes using a lot expletives. I sat for a few minutes and considered calling a tow truck to take it home until I figured out I was at least 50+ miles from there. Not wanting to spend the $200+ for a stupid tow thinking I was going to fork out even more cash to fix the truck, I started looking at where the oil was leaking from. Because the whole drive train was dripping oil, I couldn't tell. I checked the oil and trans levels and both were full. Now I am wondering if there is another place the oil could have come from?

I started the car and began looking for a leak and couldn't find any other then an occasional drip from the stuff that had been oil soaked. I made a u-turn and began heading home being real careful watching all the gages stopping several times to check if it was dripping. I stopped at a car parts store and got a couple of cans of Gunk spray cleaner and took the car to the local spray wash center and tried to get all the oil off so I would have a better chance to see where the oil was leaking from and took the car home. Where is the best places to check for oil leaks on the 4.0 I6 and has anyone had anything happen similar to this? Now I am totally paranoid seeing as the motor has almost 250,000 miles on it even though I made it home with no problems. I even thought maybe one of the locals might have played a trick with a balloon filled with oil near the manifold or something but I am doubting it.

Any help would be appreciated,

Thank You,
Robert

It sounds like you aren't sure if it is oil or transmission fluid. I have had my jeep puke transmission fluid from the filler tube when I was towing and forgot to downshift.

Good luck

This wouldn't be the first time I heard of an AW4 pushing fluid up the dipstick tube. As you said, tranny seemed full. Was it running when you checked it? Still hot? Tranny fluid expands when hot, hence the 'cold' and 'hot' markings on the dipstick. Check it running, but merely warm, after driving it around the block, having let it shift through all the gears. And, oh yeah, put a cooler on it!

Every thing points to a transmission fluid boil over. May have been too full to begin with. If there is not a separate transmission cooler on it get one!!!!

I always get my Transmission good and hot before I top it off to the full hot level, I mean summer 100 F outdoors, 30 minute run in the third gear at 60 mph sort of thing. Otherwise I fill to the cold line only in the winter after it is parked all night!

I learned that the hard way driving a new Dodge Charger, 1976.

X3 on the trans pushing oil out of the vent. BUT you were running the engine at higher RPMs than normal. Could be a blowby issue. To much crankcase pressure and the oil is pushed ouf of any spot it can. That would be the reason for the oil everywhere. The oil coming out was in the form of vapor so a little oil makes one hell of a mess. Then it hit the hot crossover pipe and you saw the smoke.
I think you made the right call on letting it cool and checking the fluids. As you noted it has lots of miles on her so keeping a close eye on vital fluids is even more important. You might try the same strech in OD next time. I will bet you were over 3000 RPMs which added to the crankcase pressure build up. Be sure the hoses are in good shape also. Another thing is pop open the air box and see if its full of oil.

Ron

All good advice here, but first I'd check the trans dipstick filler tube to see if it and the rear of the engine is wet with a good light source and a mirror. If it's dry then clean the rear of the engine where the pan meets with brake cleaner then consider jacking up the front end as high as you can get it then run it at 3,000 RPMs for several minutes and then check the rear of the pan for leaks. It could just be you need to tighten the pan gasket bolts or you need to replace the RMS.

I had what I think sounds like a similar situation. No real oil leaks, maybe minor dripping but nothing I would even put cardboard under the jeep for. On some uphill driving I would start blowing smoke bad and the exhaust pipe where it crosses over was blackened with burned on fluid.

I thought I had found the issue when I discovered my transmission dipstick tube was not connected properly. It's a 2 piece and the pieces had a good 1"-2" gap and I thought fluid was puking out from there. I fixed that and drained / refilled with the proper amount of fluid just to be sure it wasn't over full, still had the smoke blowing on hard uphill roads then no signs of leaking any other time other than the blackened exhaust pipe.

I decided to do the RMS as I've seen some minor wetness in that area, after the RMS I haven't blown smoke and I've pushed it hard on the hills trying to break it and it's been fine. You may consider doing the rear main seal and seeing, if it hasn't been done recently then you may as well.

Good advice has already been given.
I'd verify the type / source of leak if you can. Trans fluid puking from the dip stick is not uncommon on these cars when you push them hard enough. Another potential one is engine oil from the dip stick - I've seen it on Toyotas and Volvos alike. When the crank case breathing system gets gunked, sustained high RPM blowby gases will force oil out of everywhere oil can come from. Remedy on our Jeeps would be to do the full valve cover gasket job.
What else...
Yep. Clean it up as best you can. Drive it a while. Keep an eye on fluid levels. Stay vigilant, see if you can spot the leak. Post up again when you determine what it was.

If it is engine oil a new set of CCV lines and maybe a thicker oil might help.

jeepingben said:

It sounds like you aren't sure if it is oil or transmission fluid. I have had my jeep puke transmission fluid from the filler tube when I was towing and forgot to downshift.

Good luck

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+1

'98 XJ, w/only stock trans cooling