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-   -   Help needed. Mysterious leak. (http://www.wranglerforum.com/f282/help-needed-mysterious-leak-87527.html)

jeepchimp 04-01-2011 11:56 PM

Help needed. Mysterious leak.
 
Guys,

Here is the picture of the leak:
http://78.47.134.230/IMG_0452.jpg

The big bolt in the center is the oil pan. Bottom is manual transmission.

Some fluid seems to be coming out where the transmission connects with the engine block.

Anybody has any suggestions as to what that might be?

hookuspookus 04-02-2011 03:00 AM

Quote:

Originally Posted by jeepchimp (Post 1153016)
Guys,

Here is the picture of the leak:
http://78.47.134.230/IMG_0452.jpg

The big bolt in the center is the oil pan. Bottom is manual transmission.

Some fluid seems to be coming out where the transmission connects with the engine block.

Anybody has any suggestions as to what that might be?

rear main seal , hows your valve cover gasket ? rear main seal , time to pull the tranny and replace your clutch while its out

SilverTJMike 04-02-2011 03:11 AM

Is it a 6, rear main is a two piece no need to drop the transmission. If it's a 4, it needs to drop. 4-6 hours.

jeepchimp 04-02-2011 03:19 AM

It's a 4.0 L 6 Cyl Engine.
Sorry about a potentially dumb question, but the name "rear main seal" suggests that it would be in the back of the transmission block right? This leak is in the front right before the engine block. Or is that considered the back?

SilverTJMike 04-02-2011 03:31 AM

It's at the back of the engine right before the transmission . The 4.0 is notorious for rear main leaks. I just replace the one on our LJ and the TJ apparently is jealous so I am replacing it in two weeks. Not terribly difficult, just time consuming. Lots of writeups with pictured good replace rear main seal on jeep wrangler or pm me and I can post my bookmarks.

The oil will usually get blown back on to the base of the transmission. They are more annoying than anything, the may leave a few drops to small to medium spot in the driveway.

As said before, also make sure it's not the valve cover dripping down the back.

darkproximity 04-02-2011 03:36 AM

wranglers come stock from the factory with a rear main leak lol.. i have one in my YJ (I6), just drops here and there, not enough to warrant tearing stuff apart, i have other leaks to worry about (D30 pinion and now out the passenger side)

jeepchimp 04-02-2011 03:40 AM

Thanks for the help, SilverTJMike.
Here is a quick observation. I replaced the engine oil earlier today. Prior to my doing that I only noticed a few small drops from that spot on the garage floor in over 3 weeks of parking (that's when i got the Jeep). After today's oil replacement, however, the leakage really picked up. I did nothing special, just drained the oil, put about 5.3 quarts back in and replaced the oil filter that's it. So perhaps it might be just dripping down the back due to a faulty gasket like you guys said. And the reason it was not dripping as bad before is because the old oil was denser... man, that's some scientific stuff lol

darkproximity 04-02-2011 03:44 AM

what oil was in it before? and what did you put in it now? maybe its a bit thinner oil and more is able to leak out..

SilverTJMike 04-02-2011 03:53 AM

I have read switching to synthetic can accelerate the leak since they clean out all the crap that was blocking the leak before. And my rear main leak is finicky.

Lol at the rear main leak from the factory, 80% or more of the used jeeps we looked at had rear main leaks!

jeepchimp 04-02-2011 04:21 AM

What oil was in there before is unknown. I put regular Mobil 1 10W30 non-synthetic oil.
I just sniffed around the engine block, I have to say that the back side of it and half way up to the front on the passenger side (right up to the oil filter) is very greasy and wet with oil. Not crazy wet, but it's certainly not dry grease. I will have to wipe down all that grease first, and then I will be able to tell where that leak is coming out from.

Black98 04-02-2011 05:02 AM

Check valve cover area and back of top of engine 1st (open your hood all the way and use flashlight) Good chance its leaking down the back of the engine and getting there and other places

herbie 04-02-2011 10:09 PM

Quote:

Originally Posted by jeepchimp (Post 1153270)
It's a 4.0 L 6 Cyl Engine.
Sorry about a potentially dumb question, but the name "rear main seal" suggests that it would be in the back of the transmission block right? This leak is in the front right before the engine block. Or is that considered the back?

certainly not a dumb question it means rear main crankshaft bearing seal and it is at the rear of the engine block. before the transmission begins

jeepchimp 04-02-2011 11:29 PM

Makes perfect sense now. Thank you.


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