I have a 94 jeep cherokee 4.0. It is leeking a little oil which looks to be coming from where the tranny hooks to the motor. Leaks more when its running. Not a BAD leak, but any ideas on what it is? has 225xx mi on it

 

That would most likely be your rear main oil seal (on the back of the crankshaft). This was a common issue with the 4 liter, and it may not be a bad leak now, but will steadily get worse. This seal can be replaced without taking the engine out of the jeep, but you need to remove the oil pan which isn't easy or even possible sometimes without at least lifting the engine somewhat - you'll need to crawl under and have a look to see what you'd need to remove to be able to get at the oil pan cleanly. You'll also need about 6" clearance to drop the pan under the crank and oil pump intake. Once the pan is off, you'll see the rear main bearing cap - this also holds the seal that comes in 2 halves. The idea is to take off that cap and tap out the upper half of the seal without scratching the crank surface and then you can tap in the new upper and reassemble everything. It's been a long time since I've done one this way, but could probably get you on your way to doing the job if you're interested.

 

This is the culprit, you can see the seal split. The cap with the bottom bearing half and the bottom seal half is easy to remove once you have the oil pan off. The upper half can be difficult and you may need to loosen some additional caps to give a bit of slack at the back end to be able to tap it around. I've used wood doweling to get it started and then grabbed the end with some vise-grips to pull it all the way through. Put the new seal half into place before tightening anything back up & if you've loosened any other caps to give the crank some slack, retorque all the cap bolts on assembly.