beefmobile

Hey guys, i haven't been on in a long while. I've also only owned YJs and XJs, so this is my first "Grand" Cherokee haha. Anyway, so far i'm REALLY liking it. She's got a whopping 253k miles

So far, i've replaced the plugs, air filter, oil and filter, wheels and tires, diff fluid, added the missing passenger side mirror and headlight, cleaned out the buckets of animal crackers and chicken nuggets, and battle the cigarette smoke smell (semi-successfully).

It's got the (i assume) NP242 with all time 4wheel and part time 4lo. I thought it was a little odd that there was no way to get into 2Hi. Roof rack, tow hitch, aftermarket CD player, electric everything, auto, 4.0, etc etc.

My first issue was the **** was ALL over the road on the drive home from buying it......like i was driving drunk, high, and half asleep. To the point where it was getting dangerous. There was intermittent clunking odd noises. I was just trying to make it home. I ended up putting the old wheels and tires from my XJ on and it solved the drunk driving problem. I noticed every tire was different.....so maybe i was experiencing some serious "radial pull".

Then, my girlfriend, who was driving behind me in the trusty XJ, noticed the ZJ was smoking and STANK. I pulled over and noticed the Dana 35 was cooking itself. Smoke pouring off of it, boiling. Had to leave it there until the next day when i towed it to the shop i work at. Pulled the diff cover and it filled the shop with the nastiest, dark, gut wrenching smell of burnt diff fluid that damn near made my eyes water. It was like black metallic molasses. Cleaned it out completely, made sure everything at least *looked* ok. Sealed it back up with RTV and filled it with Royal Purple 75w90 with friction modifier. I went ahead and picked up a Dana 35 from the salvage yard just in case the bearings were out in the current one. I decided not to swap it in because it's shown zero problems since then. I'll see if it shows any more signs of being shot, and if it is, i have a spare D35.

So on to the check engine light....

I get intermittent codes of 12 21 55, with 21 the only one i'm looking at. I have noticed what seems to be decent exhaust leak at the manifold. I've been meaning to replace it, along with the valve cover gasket, but haven't had the time or motivation.

From what i've found, code 21 means "problem in the oxygen feedback circuit". So the first step is usually replace either the upstream or downstream o2....but could the o2 be getting a bad reading because of the exhaust leak?

Thanks in advance for any help. I'm digging my new ZJ!

JstGtnStrtd85

Welcome to the wonderful ZJ i have a 97 with a whopping 266k on her.. As far as the o2 sensor... An exhaust leak can trip them... Just to be on the safe side with that kind of mileage fix the leak and replace both sensors for extra insurance. Dont want to go through replacing one just to findout that the others bad..

beefmobile

Ya i figured since the o2's job is making sure the air/fuel is correct, that maybe the air/fuel isn't correct haha. Most people's first reaction is that the o2 is malfunctioning. I'll be replacing the exhaust manifold and valve cover gaskets probably this weekend.

I was really admiring my ZJ today. I took the lady out for dinner and we rode in it. Smooth, quiet ride, but you could feel the 4.0 and all time 4x4 in the background of the ride. Very reassuring. Hell, we swung by Academy and i "accidently" took the wrong entrance to the Lowes parking lot, so i hopped the curb and climbed the muddy hill over to Academy for a few seconds of fun. Totally worth it. The ZJ swallowed the hill like it was nothing.

dave1123

While you have the valve cover off, clean out the head oil drains. inadequate oil drains will hold enough oil in the heads to be above the rim of the head and cause it valve cover to leak. I've seen this problem SO many times on V8s I could write a book. Chevys are the worst because the oil drains are just a 3/8" drilled hole.

ShinySideUp

If you don't have any way to put the transfer case in 2 Hi, you have the Np249 transfer case. You might want to look into a replacement Viscous Coupler - this could have caused your axle issues. The failure mode on the VC seems to be it locking up. It can be caused by having different sized tires between front and rear. (ask me how I know...) To test it, head for an empty paved parking lot, and do a couple of full-lock figure eights... you'll know that something is up.

You'll find that your 95 Grand will go anywhere you point it. We recently had some ice, and then snow on top of it where I live. Expensive cars with traction control in the ditch everywhere. But not my old ZJ with the prehistoric solid axles.

dave1123

With the same snow-over-ice setup, I love to drift in 4WD!

beefmobile

Man I never even thought about the tire size issue. It may have been a different tire size on the rear tires, as I mentioned every tire on it was different when I got it. It was swerving all over the road uncontrollably, too.

As soon as I got it home, I put my XJ's old wheel & tire setup on it and changed the diff fluid. Everything was as it should be. I still haven't had any problems.

beefmobile

On the viscous coupler.....i noticed that when doing sharp turns, i get a clicking noise. Doesn't sound *terrible*, but it is there. About the speed of what the driveshaft would be. Is this the VC?

dave1123

It is my understanding that the viscous clutch is like a torque convertor in that it's two turbine wheels sealed in a case with fluid. Any difference between driveshaft speeds between front and rear is absorbed by the fluid. If the front driveshaft is removed, the fluid will overheat because of the slippage and destroy the coupling. This can also happen with different size tires as well but slower.

In order to replace it, the entire t-case must be taken apart and the price of the clutch is not pretty. This is the point where many people start looking into a 242 swap.

Your "clicking" is probably a CV joint or bad axle end u-joint.