94david

New to forum but need help.

"Just" bought 94 J GC Laredo zj 4.0 L I6 for $2500, 89,000 miles (in Feb). Looks great w/many new parts.

Problem 1: front axle diff blew out after 24 miles. tried to get diff rebuilt but housing is damaged. I can get a used axle installed for about $900.

Problem 2: trans shop mentioned the infamous viscous coupling. It has a 249 transfer case. I though the 249 was only in the V8's?

I've done a lot of online research and here's where I am:

Thinking of swapping 249 for a 242 or a 231 (so I avoid the VC problem and have 2 WD option (not to mention the 4low front/rear axle disconnect problem).

I am not a mechanic, but understand the concepts. I've read procedures for the swap, but my mech is good w transmission and differentials but may not normally deal w/this detail of change (shafts sizes, slip yokes, getting right 242/231 to fit, machining parts, etc.

Installing this may cost another $1000


I only plan on using for the winter and as a backup for my 95 corsica (243,000 miles), and I'm on a low budget.

So, sorry for the long start but any thoughts in any direction would help me from having a breakdown (mental)/

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dave1123

Welcome to CF and the crazy world of jeepin'!

The best resource for info on the t/cases is this; http://jeepforum.com/forum/f13/trans...1-np242-685644. Check it out.

Just keep in mind that the 4WD ranges on the np231 are part-time, meaning they should only be used on slippery surfaces whereas the np242 has the full-time option.

94david

Thanks. The 231 would be fine for my use. I read through the doc you referred to. My concern is it seems to need a jeep expert or is a project for one who will work on it as a hobby, taking their time to work out all details. Shop want to get things fixed and out the door w/out lots of running around and researching.
But thanks again

dave1123

You are right about the 249 mostly being in V8 jeeps, BUT the original purchaser could have ordered it any way he wanted it. For the most part the 6's had a 242 and V8's had the 249. The Cherokees (XJ) had the 231.

If you found an I6 with a 242 from '93 to '95, it would be a bolt-in.

rangermonroe

I am dealing with the VC issue right now.

Loads of fun. Replacing it yourself is pretty simple if you are mechanically inclined.

$900 seems about right, if it is a known good diff, or at least rebuilt.

94david

From what I have read swapping is a bit more than a bolt in. There are diiferences w/shaft lengths, yokes, and (for a post 94.5) the gear cut.

I appreciate all the help. I like the 242 idea a lot but since work is being done by a shop (quick in and out) I think I will opt for a new VC. At least I shouldn't have to worry about that part for at least 80,000 miles.

Regarding the front axle differntial, it is just a used one from a junk yard. Shop wanted $2500 to put in a remanufctured one (not even rebuilt).

As it is I expect I will be paying approx. $2500 to repair a truck I bought for $2500, and haven't even driven 1 foot yet. If I had only known.

If the truck lasts another 40,000 w/o any more major problems I'll be happy with it.

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dave1123

OH!!....WAIT!! I was overcome by a pretty face and bought a '97 ZJ for $1800 and 2 months later put $3000 into the transmission! It needed lots of hard parts and a pump. Then 6 months later the rear axle blew up. That was my first jeep. Boy, did I learn fast!

94david

Should be getting jeep back in a few days. Will let you know how it went.

Question for now is the infamous Death wobble. Read some online and know many part could cause it. Saw good description of how to find correct parts to check before replacing to many things.

Q: Mine does not have a lift kit. How suseptable is th 94 GCL to death wobble, assuming stock suspension and steering.

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dave1123

Death wobble can occur in any vehicle with this suspension and axle design, but is more often started with lifted ones. Any looseness in the bushings and pivot joints or bad hub bearings and tire balance can cause it. On the other hand, my '97 ZJ had REALLY bad ball joints and never got the wobbles, even after going over bad train tracks.

94david

Mostly just status update. Had a used front axle/differential assembly delivered to mechanic yesterday but it was no good (rusted out "spring holders"). It was sent back and junk yard is looking for another (paid for and warenteed).

Its too bad, it reportedly only had 96,000 on it.

I've had junk yards looking for one for two months now. Is the 3.73 gear ratio unusual? They can find several with 3.53 but not the 3.73. Source need to deliver it to Staten Island and warentee it.

I have a problem spending $2,000 for a re-manufactured one (like the mechanic wanted to do) plus labor. A rebuilt one may also cost $2000 delivered.

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dave1123

For the most part, the 3.73 came only in ZJ's with the tow package. The most common ratio is the 3.55. Jeep gave the original purchaser the option of ordering what ever he wanted, including axle ratios and t/case choices. That's why a V8 ZJ with the 242 t/case is rare. Most were made with the 249. The tow package jeeps had a trailer hitch, an aux trans cooler, and a trailer lighting module installed. The lighting module converted the separate turn signals to the standard 2 lights on the trailer.

AFAIK, the only difference between a remanufactured axle and a rebuilt one is the company that did it. Typically, a re-man is done by the manufacturer whereas a rebuilt is done by a shop specializing in rebuilding it. Basically, all new gears and bearings are used in a re-man, whereas a rebuilt the gears are inspected for wear and all new bearings are put in and aligned.

94david

Its a 4.0 I6 with a 249 Tcase.

Is there a way to check if it should have had a 3.53? (maybe a previous owner threw in a used 3.73 and then sold vehicle before damage occured?).

Didn't notice a trailer hitch and don't have the vehicle to check.

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94david

I meant a 3.55, not a 3.53.

Found that front and rear need to match. Possible to change but both need to be changed (at least ring and pinion)?

Also, many people are calling the front axle differential the "rear differential" . If it only drive the front wheels and is located in the front why are they calling it a rear differential? What would the differential at the rear be called?

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dave1123

IDK who you've been talking to, but the front differential is the front differential and visa-versa. Also if he put a 3.73 in the rear, he'd have to remove the front driveshaft or it would have destroyed itself before it got down the block! There should be a tag under one of the diff cover bolts telling you the ratio. Whatever the rear diff is, the front must be also. If the tag is gone, the BEST way to tell is to pull the cover and count teeth. The ring gear tooth count divided by the pinion tooth count is the ratio.

You know what? Maybe that's why your front diff blew up and wasted the viscous coupling. Mismatched ratios. I don't even want to THINK about the stress put on the rig if that is the case. If it was a 242 or 231, it probably would have shattered the t/case.

94david

Thanks again. You always provide good info.

Junk yard found another 3.73 front differential but with same rusted out "spring holder" problem. Is this common?

If I put a 3.55 in the front would I just need to change the ring and pinion in the rear to match or is there more involved? (I know there's a difference of torque vs. fuel economy).

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