So I find this 99 jeep grand cherokee limited while I was out doing warrenty repairs for work. (I work for john deere)
It was setting in a customers yard under a tree, looked like it had been there a little bit. I inqure about it while I am working on his mower. He said the engine was bad. His discription was it started losing power while coming home one day, then blew a rad hose. He replaced the rad hose but ever since then it had a good miss to it. He replaced the plugs and coilpack, but still had the miss. He said he then heard bubbleing in the heater core and just gave up. Set for about 6 months. I'm thinking he just blew a head gasket. It does start and run he said, just misses, battery is no good either. Jeeps fully loaded, power everything, 4.0 straight six, but only 2wd.
Long story short I buy it for a pretty decent price (1k) thinking a good chance to make a little money. Fix the engine and then clean the thing up, fix a couple small items, and turn around and sell it. Books for around $3-3500. He said everything works. We boost it off and drive it onto the trailer. Engine ran nice, no knocking, ticking, or any noise other than the miss.
Compression check reveals #1 cyl has 60 psi, the rest are good. Pull the valve cover and man this engine is clean on the inside for 179k. Pushrods, rocker arms, and valve springs all appear fine. Pull the head and the gasket is not blown, head doesnt appear to be cracked, wtf? I then turn the engine over by hand (#1 just happened to be at tdc) and I saw it. A few chunks of piston stuck to the top of the cyl wall. The cyl wall itself has no damage and no scratches, can still see crosshatching on it and all the the other cyls. I take a screwdriver and the peices flake off. I drop the pan, take loose the rod and pull the piston. Dont know what happened, but the peices on the wall had come from the piston. Bore and bearings are standard, so its never been rebuilt. Bearings looked real good. I go to a machine shop, buy a new piston, have them check the head and clean it up, went ahead and had them do a valve job. Borrowed a bottle brush hone from work and just knocked the glazing off the cyl wall, cleaned up real nice and easy. Theres not even the start of a ridge at the top of the cyls. Put everything all back together today (took all day, but I got it) and fired it up. Fires right up, held it open to seat the new rings on the new piston. and it runs like a dream. Just as smooth and quiet as you can get. I am getting really excited.
I put all my tools up and take her for a spin. Everything is good untill I get on the road. 1st and 2nd do just fine, but when it shifts into 3rd, its just not there. Just like it goes into neautral. You really dont even feel it shift out of 2nd. you just get up to around 35-40 and rpm's go up, but nothing else happens. It will finally shift into something after letting off the gas and hitting it a few times. When it does, theres a grinding/whining noise that changes when you hit the gas or let off. Kinda sounds like the rear axle is going out, but everything is quiet untill it does finally hit that gear. So I'm thinking its the trans itself is making that noise. Once it got into that gear, if I get above 50, I get death wobble, it also pulls to the right just a bit. I get home, put it in neautral and try and shake the driveshaft to see if it might be the rear axle making the noise. Feels tight. I rotate the ds back and forth what I can, and I can hear rattleing metallic noise coming from the trans, like something on the output is loose or worn out.

What a flippin let down. I was so proud of myself after I got it running and it ran so good. I was thinking I did good and lucked up onto a good deal. But now my good deal has turned into a nightmare. I had to borrow the money from my dad to buy the thing, with the promise to give it back when I sell it. I have spent a little over $400 getting it running again. Its wintertime and I dont get any overtime anymore, so I dont have as much money as I do during the spring and summer. I am now trying to decide if I want to keep going and replace the trans, or try to sell it for $1500/needs work and try and break even. The more I spend fixing it, the less profit I make when I sell it.
Just kinda bummed/pissed at the moment.