Went wheeling, found new problems.

98 XJ 4.0 As the title would lead you to believe, went and did some light wheeling today. Been a while. But thats not the problem. As the trails got more uphill and I went into 4wd, I started to get creaking/popping noises from the front end. Only in 4x4, in 2x4 no noise. Im thinking axle u-joints, as it sounded to be happening out towards the wheels. What's the easiest way to check these, and can a guy with basic hand tools change them in a parking lot?

Problem # 2 was the electric fan. After a while of crawling along my temps were near 220 by guage. Before long it was creeping to redline, I had to shut it down and let it sit, thats when I quit wheeling and went to faster moving roads. Shouldn't the fan turn on around 210? I checked the relay and fuse for the helluvit, no turning on. Ill try and straight wire it tomorrow, see if it's the fan. Seem likely?

Problem #3, when I got home and looked things over, I noticed oil on the front driveshaft, front of crossmember. Couldn't see a direct leak anywhere, it was strange. Where would there be a common oil leak at the rear of the engine area?

Otherwise it felt good to be on the trails again, the XJ impresses me every time.:thumbup:

i don't now about your first and third problem but i can speak on you 2nd as today i checked my fan because i had a feeling it wasn't working and found that the electric motor that runs it is shot (i did the old pull the plug on the tstat and the aux fan will auto kick in if working). So i'm off to NAPA tomarrow for a new one.

Prob #1. if you jack up 1 side, remove tire. Rotate the hub back and forth, the inner portion of the axle shaft (closest to the diff) should turn at exactly the same time the outer portion of the shaft (closest to the wheel) does. If the joint is shot, you will see movement in the joint, before the inner portion of the axle shaft moves. Another clue is lack of lubrication; The joint will appear rusty, not sort of 'wet' with grease.
Could this be done in a parking lot? I SUPPOSE so, but personally I'd rather not tackle something like that, unless I've had it apart before and know that everything was not overtorqued, and I used anti-seize on the bolts/hub. The 3 12point hub bolts can be a &$& to get out and so can removing the hub from the knuckle; getting the joint out is usually not fun either. There are writeups on this, do a search: remove hub, axle shaft u-joint, etc....

Oil leak is probably from the valve cover. When cool, you should be able to fit your hand between the head and the firewall and see what is on your hand when you bring it back.
Another possibility is the pinion seal on the front diff. That one should be easy to tell.

mucovich: Didn't know about the pull the CTS trick, I will try that tomorrow.

tommyr: So pretty much like a typical driveshaft u-joint , but behind a bunch of stuff. I have a $35/hour mechanic just for job like this. They look dry and caked with mud, just like the rest of the jeep... Is there anything else up front that only turns in 4x4? Wheel bearings perhaps? I hope not.


Jess: Not the front Diff, so Im thinking up along the firewall somewhere. Really looked like it was falling directly onto the front driveshaft a bit ahead of the tranny x-member.

Thanks all for the help and suggestions. :cheers:

i forget to type lol, anyway, it might be your rear main seal, i know of a few people who have had that go bad, mine was starting to at 130xxx on my old cherokee, glad you got to go wheelin!

98XJSport said:

tommyr: So pretty much like a typical driveshaft u-joint , but behind a bunch of stuff. I have a $35/hour mechanic just for job like this. They look dry and caked with mud, just like the rest of the jeep... Is there anything else up front that only turns in 4x4? Wheel bearings perhaps? I hope not.

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Yup, typical u-joint. Unless you have a disco front axle, everything turns in 2wheel drive, just like it does in 4 wheel drive, only difference is the parts are under load when you are in 4WD. Wheel bearings could be bad, but I think U-joints more likely. Bearings have to come out to do the U-joints so the cost there would be parts only (about $80ish each, though) I do this stuff for myself & dabble in it for friends/co-workers who would rather pay me the $35/hr than the dealer's $105/hr

1998 fan on 218*; off at 209*.

Ok got a chance to troubleshoot a bit yesterday. Pulled the CTS, kicks the fan on every time. So it's not the fan. The sensor itself is just over a year old, I will run through the wiring on it just in case, but that's not likely. Where do I go from there? Im thinking of mounting a switch to power the relay, anyone know of a writeup?

As far as the oil leak, I think the rear main leaks normally, and when it overheated it started leaking out the valve cover. No new leaking since. Ive changed the valve cover gasket on a wrangler with the 258, I doubt this is much different.