Jburtonart

Okay, so I recently bought a used 99 Jeep Cherokee Sport 4.0 (T242 Tcase, Chrysler 8.25 rear) with 144k miles on it. So far it's received some new gaskets, and new sway bars/bushings to replace old worn parts. I've got an all new exhaust header-back, and shocks/struts to install soon. Keeping it stock as far as suspension goes for the time being.

One issue that has become more apparent as I've had more time to get used to the vehicle is that something is up with the front end. I'm a little new at this, but I'm heavy into reading up on this stuff lately - excuse any ignorance on my part.

I get a soft whomp-whomp that may be the front drive shaft area at about 60mph that turns into a louder vehicle vibration at 70-80mph. In 4wd full time I get a louder, grumpy, grindy noise from the same area at about 30+mph that only happens when I'm on the gas. I also get wheel hop in 2wd when making a sharp, slow turn - but ONLY when turning to the left.

One specific question I have to put out there: should this front drive shaft have ANY play at all when I grab it and shake it? On either end (tcase or axle)?

I figured I'd drop this here to look for some suggestions that I may not have come across yet overall. I'm hoping that these issues are somewhat related, which would save me time and money so I can buy/save for fun stuff.

RTorrez1

Start by checking your u-joints you shouldn't have any play in your drive shafts. The wheel hop could be your shocks or bad tires. Just some things to check.

Jburtonart

Thanks! Is it normal to have some rotational play in the shaft?

Another thing worth mentioning is that I've had the seal at the tcase and front shaft replaced, then again in less than a week and still leaking yet again. Probably caused by the vibrating issue? My guess.

U joints don't seem bad on visual but may take some stuff apart here this weekend and try to get this thing figured out. Any other tips welcome.

I ARE EL1TE

Yep, some rotational play is acceptable. Just make sure that the play is inside the diff and not in the different parts of the driveshaft.

Harky1949

Could be front drive shaft... You can check it by taking it off and seeing how it drives. Same with the rear. Process of elimination.
I have a vibration problem on my 96 that goes completely away when I take off the rear DS. (I run it in 4 Part-time as a front wheel drive...smooth).
There is side-to-side play in my slip yoke that is probably causing the problem.
Also, the "wheel hop" when turning sharp in 4WD is caused by the front axle U-joints. As long as there is no clunking or grinding, it's probably OK. Mine does that, too.

Jburtonart

Maybe asking something more specific will help me find this quick. What is at work, if anything that would cause noise on the front end in 4wd full time, but not part time? Any links for reads on the 242 and 4wd system are helpful - I'm looking for this stuff but not finding what I'm looking for.

Jburtonart

Also - thanks will definitely be trying a run with the front shaft off.

HiPoint

The NP242 uses a center differential in Full Time mode that allows a 40/60 split of power between the front/rear wheels allowing you to turn without binding on dry surfaces. I've never had one apart so someone else will have to chime in on diagnosing the problem.

dans98xj

you might want to try adjusting your linkage to the case. it sounds like it is stuck between part time and full time and part time and 2wd. you have to shift threw part time to get to 2wd from full time and the other way around. this could be your issue. when you remove the front shaft and the problems go away this would be the next thing to look at.

Jburtonart

Hm.. okay. On removing the front shaft; once I have it out is it safe to put it into 4wd full time and zoom around a bit to try and reproduce the sound I've been having? I would assume so, but don't want it freaking on me.

dans98xj

yes you can drive around with the front shaft out in full time 4x4 or even part time 4x4. just don't shift on the fly, shift in and out wile stopped in neutral, or you could damage the case your front drive shaft moving at the same rate as the rear enables you to shift on the fly. hope this helps.

Jburtonart

Thanks much. I'm still willing to test it out some myself this weekend but I had a mechanic right near my work put it on a lift. Verified the sound is generated by the tcase.

Shaft Ujoints all seem okay - a very tiny amount of play in front axle ujoints (maybe 1/16'', if that), even amount on both. No play at any of the bearings at all. Rear tires move in and out a very slight amount , maybe 3/16''-1/4'' most, when pushed and pulled on with both hands together. No up-down or side-side rock to them though.

Tcase has been leaking, can't be sure for what amount of time sadly. I'm seeing these 242's used on the webs for $150-200 (on ebay etc.) Is there a better way to do this if I'm going about getting another tcase, like a rebuilt with a warranty? Looking for a trustworthy source on that if so. Thanks for all the help.

kgm

The u joints shouldn't have any play. Are you feeling the play of the gearing? Or play between the 2 shoulders that the u joint connect? They should be tighter than a virgin on prom night as goes the parlance of our times

Jburtonart

So bit of an update with questions... At this point I've gone ahead and found a low mileage transfer case and had it replaced. Now I have a tcase that doesnt leak but my situation isnt much improved otherwise really.

I removed the front diff plug today to find somewhat dark fluid with metal specs in it.

I also removed the front shaft finally and drove it around. At first I put it in 4 full time and drove a short distance down my street, after which it stopped applying power to the rear while I was driving and made a sound as if the tranny were just spinning free in a noisy neutral. I shifted out of 4wd, drove, and tried to go straight back into 4full time but got a thud/boom sound and more free spinning/no power. This has me semi worried. I shifted into part time and it does fine, haven't tried 4low yet. Is full time supposed to work without a front shaft? Would it not think the front wheels are spinning free and try to apply all power there? Hoping for the best.

On the bright side... When I took it out on the interstate I have no more bad sounds at 70-80mph. With the front shaft on I was getting some resistance when I hit the gas as well as a constant low rumble that sounded as if it were from the rear.

Any help or advice is appreciated!! Thanks so much.

Jburtonart

May help to mention I'm looking for advice or reassurance on the front shaft causing a high speed rumble. My thoughts are to just replace the shaft and ujoints entirely and see what happens - but I love any cheaper fixes. As far as the front axle... Pinion bearing? What am I getting into there and should I bother trying if I havent before or start saving for some shop labor? Ha