[Wenatchee_Kid]

Yeah, you think I'm a newbie, and I think congratulations are in order.

Wifee brought home a Black 2001 Laredo package Grand Cherokee, paid for. Leather. Nice ride! It was like falling in love again in high school, I just loved it, except for that pesky mystery engine knock. Not like a Willys four-banger, at all.

It didn't quite make it up the last grade to my 4000 ft ski area. It had 154k on the 4.7 litre engine, had been running sludge for motor oil.

So we were out another $6300.
Not complaining, seriously. Dd I mention nice ride?



Guys (gals? feel free to jump in here), although the 4x shift lever reads '4whl All-Time" in the forward position, the chassis rolls in, and will get stuck in, one-wheel drive. Is that the design function? As in, either this model has no 4WD at 60mph, or I am broken.

The alternative, "4 whl low-range" works great, but is, well, granny-gear type low range, revving pretty high at even 15mph. Tyical of this model?

No tranny designation on the body; manual just states that the axles are locked together in 4X low-range.

Will a stock WJ make it over Naches Pass?

Thanks from a newbie. The Wenatchee Kid

[ezflip]

The 247 transfer case in "all wheel drive" will send torque to where its needed. While stuck, you should have one front and one wheel spinning unless you have vari lock axles found only in Quadra drives. If only one tire is spinning, the progressive coupler in your transfer case is toast. You can try a fluid change with dealer only 247 fluid, but chances are, the damage is done. Look into swapping transfer cases.

[billzcat1]

Originally Posted by Wenatchee_Kid

It didn't quite make it up the last grade to my 4000 ft ski area.

Stevens Pass? That last section up to the top of the pass is pretty gnarly.

Originally Posted by Wenatchee_Kid

Guys (gals? feel free to jump in here), although the 4x shift lever reads '4whl All-Time" in the forward position, the chassis rolls in, and will get stuck in, one-wheel drive. Is that the design function? As in, either this model has no 4WD at 60mph, or I am broken.

The alternative, "4 whl low-range" works great, but is, well, granny-gear type low range, revving pretty high at even 15mph. Tyical of this model?

This sounds like broken. The V8 Laredo model had the QuadraTrac II system as standard equipment which uses a transfer case known as the NV247. This transfer case operates in rear-wheel drive until wheel slip occurs. At that point, the case generates hydraulic pressure which compresses a clutch pack, transferring torque to the front axle. This assembly is called the progressive coupler. It is supposed to react in 40ms when wheelslip occurs.

A very common issue is that service stations (even dealers) put the wrong fluid into the transfer case, causing binding and vastly accelerating wear on the clutches. This was because the original specification in 1999 was for ATF+4 fluid (transmission fluid). By mid-1999, they found this was not working in real-world application and issued a TSB to change it to a special hydraulic oil... but by that time most of the service documentation was already getting written - Haynes, Chilton, AllData.

When the progressive coupler wears out, it loses the ability to lock up and transfer torque to the front axle, but 4 LO still works fine as this bypasses the progressive coupler and locks the transfer case. Don't use this mode on pavement - dry or wet.

Swapping the complete transfer case with another NV247 is the easiest fix. The progressive coupler can be replaced, but the coupler itself is $400 plus labor. Another option that takes a little more ingenuity is to replace the transfer case with the NV242 from a SelecTrac model - this usually entails tinkering with driveshafts and the shift linkage. The most straightforward swap is same-for-same.

[Wenatchee_Kid]

Thanks for the answers. Maybe it is working fine. Not sure if the LR and RF engage simultaneously while stuck. But I don't feel 4X kicking in automatically. OTOH not sure I had developed wheelslip . Fooling around on a snowy parking lot (yes, Stevens Pass) I spun it out without feeling the front pulling.

How would I check to be certain it's working?

In a practical way, I really like what they did with the design. It's just fun to drive.

[billzcat1]

I'd say you've already given it a good test. But you can put it up on jackstands and put it in drive and see if the fronts start spinning on their own. Fooling around on snow is a pretty good indication you had wheel spin going. If you are accelerating on snow in a straight line, you can give it heavy throttle (not full) and see what happens. If it isn't working, you'll get a big burnout in the back without much forward progress. If it is working, you will probably get some wheel spin but take off forward pretty quickly (assuming your tires aren't garbage).

I like WJs too.

[lauderdalechad]

The best way I have found to test any "full time" transfer case is to go to a gravel road/parking lot and from a dead stop give it enough pedal to spin the tires to kick up the gravel....if you can spin the rear tires through half of first gear without the front axle engaging and pulling the jeep forward your coupler is shot

[Wenatchee_Kid]

Originally Posted by billzcat1

Stevens Pass? That last section up to the top of the pass is pretty gnarly.



This sounds like broken. The V8 Laredo model had the QuadraTrac II system as standard equipment which uses a transfer case known as the NV247. This transfer case operates in rear-wheel drive until wheel slip occurs. At that point, the case generates hydraulic pressure which compresses a clutch pack, transferring torque to the front axle. This assembly is called the progressive coupler. It is supposed to react in 40ms when wheelslip occurs.

A very common issue is that service stations (even dealers) put the wrong fluid into the transfer case, causing binding and vastly accelerating wear on the clutches. This was because the original specification in 1999 was for ATF+4 fluid (transmission fluid). By mid-1999, they found this was not working in real-world application and issued a TSB to change it to a special hydraulic oil... but by that time most of the service documentation was already getting written - Haynes, Chilton, AllData.

When the progressive coupler wears out, it loses the ability to lock up and transfer torque to the front axle, but 4 LO still works fine as this bypasses the progressive coupler and locks the transfer case. Don't use this mode on pavement - dry or wet.

Swapping the complete transfer case with another NV247 is the easiest fix. The progressive coupler can be replaced, but the coupler itself is $400 plus labor. Another option that takes a little more ingenuity is to replace the transfer case with the NV242 from a SelecTrac model - this usually entails tinkering with driveshafts and the shift linkage. The most straightforward swap is same-for-same.

Acrually, it was working so smoothly I couldn't tell it was engaging. But your comments here were key in getting me to grasp it.

[Wenatchee_Kid]

Originally Posted by billzcat1

I'd say you've already given it a good test. But you can put it up on jackstands and put it in drive and see if the fronts start spinning on their own. Fooling around on snow is a pretty good indication you had wheel spin going. If you are accelerating on snow in a straight line, you can give it heavy throttle (not full) and see what happens. If it isn't working, you'll get a big burnout in the back without much forward progress. If it is working, you will probably get some wheel spin but take off forward pretty quickly (assuming your tires aren't garbage).

I like WJs too.

Everybody who has 'em likes them. Take a look at Craigslist, most folks add something like "I really don't want to let it go" of "This is a really nice ride" or "It's really tight."

[Wenatchee_Kid]

Some bozo took out me Jeep. The fact that I nearly died barely phased me; the fact that the Jeep was gone was onerous.

[Wenatchee_Kid]

Anyway, lookin' for someone who wants the new engine I put in it. 14,ooo miles, and it got 21.5 mpg on the highway.

[Wenatchee_Kid]

See the classifieds. Anybody care to dial in the fair asking price? 4.7 liters.

[Wenatchee_Kid]

I am conflicted about getting a lift kit. I want ground clearance but don't desire the aftermarket off-road look.

[Wenatchee_Kid]

Anyhoo, after this pont I'll have the 25 posts necessary to get on the classifieds. Wish me luck.
Gentlemen, this noobie wants to say thanks for all the available knowlege here, and for the spirit of the forum itself.

DRIVE SAFELY, hear?

The Wenatchee Kid.