I had just gotten the xj unstuck because my gf got it stuck on a muddy trail and about 100 ft from the mud spot I swore I heard a 2 stroke dirt bike behind us. I put the jeep in park and the noise got even louder it sound like it acceleroted from the tranny, so I turned it off when it was off I let my foot off the brake and it kept rolling. I took it out of 4 wheel drive and it stopped rolling. I let it cool down for a couple minutes because I was kinda whomping on it to get it unstuck throwing it in reverse and drive a couple times. So after it cooled down I start it back up and everything sounds normal I put it in 4 and normal? It drove fine the rest of the trail! But I'm confused on what the sound coulda been and should I be worried? the trail was pretty muddy and wet. Thank you.

 

your linkage may of gotten moved a little underneath causing it to not be in gear all the way

 

Today it overheated and was making a terrible whining noise when it was idling but not when I gave it gas it got louder when I put it in park

 

The whining noise is the same as the dirt bike noise, or unrelated?

The dirtbike noise is most likely your linkage, as the other poster suggested. (Although impossible to tell without being there, obviously.) Mine makes a similar noise when I have to put her in 4x4 from a standstill (ouch, not something I try to set myself up for) as she struggles to get everything aligned and into place.

The whining noise could be a fan...or a belt if it goes away upon acceleration. The best thing to do is pop the hood and take a look.

 

I don't think so this sound was a little less deep it also seemed like the engine was revving higher than normal especially when I put it in park it would
Rev even higher

 

So I guess it was very low on anti freeze which is weird cuz I just topped it off a week ago and I have no leaks other than the oil sending unit I think but I know oil is dripping not anti freeze where's it all going?