97 XJ on skates, please help.

I have a 97 XJ. Whenever I pull into 4wd, it feels like I put down a wheel right in the center of my Jeep. It wants to push, and wonder uncontrollably. It has all new bushings in the front end, new trac bar, new tires, and the alignment is on with a tape measure. It has a 2" budget boost, but other than that it is all stock. Had this problem for a year now and nothing I do seems to change it. Any help would be greatly appreciated.

When you put your Jeep in 4wd? As in on the road? At highway speeds?

It seems worse at highway speeds. When its dry in 2wd, I have no problems. Just drove to work in 2wd because I was afraid to pull it into 4.

Umm...

Are you running an NP231 or NP242?

Are the roads paved and dry?

Four wheel drive is a no-no on dry pavement.

All wheel drive is different, and can be used on dry pavement.

If you have an NP231 you should only be putting it in 4wd when you are in the dirt or snow or something that will allow the tires to slip. If the tires can't slip you are destroying something while trying to use 4wd.

I believe an NP242 allows that slippage internally. I don't have one, but I expect the shift lever is marked with something that would indicate all wheel drive.

Which transfer case do you have?

It is a 231. Yes I am only using it on snow/ice.

How long have you owned it? And during the time you have owned it did the 4wd work properly?

I am wondering if a PO might have swapped a JY front axle with a different ratio.

I have owned it about a year and it has done it the entire time. I put it up on the hoist last night and marked the tires and turned the drive shaft. It seems to line back in the same spot. I am going to pull the diff covers tomorrow night and count to be sure.

I note that there has been some front end work and alignment, and wonder if in this process it got too much toe-in or if there's something still loose. If there's any play in the system, an unpowered front end will tend to toe out (hence the usual call for a bit of toe-in on rear drive cars), but a powered one will tend to toe in under power. It doesn't take much or either to mess up handling, so , though it's a bit of a long shot, I'd double check the alignment. A tape measure is a poor gauge unless you've scored the tires.

If you have a chance, get a big piece of chalk, or in a pinch, some cheap spray paint. Take a two by four or other block of wood, drive a nail partway into the end, and snip off the head. Bend the nail up a bit. Now with the steering centered, on a decently flat surface, jack up each wheel just enough to spin it, coat the tread with chalk or paint, and slide the nail-studded wood on the floor until it makes a nice clean score on the tread of the tire. The exact location does not matter, as long as it's a steady score all around the tread. Do this on both sides, and let the car down. Now if you measure from score to score, at the center height of the tire, the difference between front and rear will be the exact toe-in, no error from tire warpage or poor guessing.

The spec for the XJ is zero toe-in.

Matthew Currie said:

The spec for the XJ is zero toe-in.

Click to expand...

I believe, it's more like 1/16" to 1/8". Prefered toe is .25 degrees, with a range of 0 to .45 degrees. Chapter 2 page 6 of the FSM.

OP:
And this may seem like a dumb question that we "assume"; are all 4 tires and wheels the same?

Is the front locked or has a Limited Slip differential? This can cause understeer in 4WD on Ice and Snow, especially on ice.

~Ron

It does have four new firestone at's on it. I had the problem before I put them on. In fact, that's why I did it. It had goodyears on it that were the same kind but different runs and I had 3/4" difference in height.

WB9YZU said:

OP:
And this may seem like a dumb question that we "assume"; are all 4 tires and wheels the same?

~Ron

Click to expand...

What he said. Mismatched tire sizes, (or mixing used/worn tires with new) can cause all kinds of hate and discontent in the drive train.

That answered that...lol!

double check gearing then.

As an aside. An np231 is going to push during turns. It's the nature of the beast. (No center differential)

Just to get this out of the way, could the wandering possibly just be road conditions? Someone mentioned earlier about rechecking the front alignment. I'd go a step further and recheck the front end parts.

Also, no it has no lockers or posi units. I looked when I serviced the diffs right after I bought it. I did not count teeth when I was in there.

I think if you are having problems with different diameters of tires or different gear ratios, it will often have difficulty coming back out of 4Wd to 2WD. If it takes a while to pop back into 2WD, or requires stopping and reversing, I'd definitely check that.

Road surface could also definitely be a factor. Solid front axles are often not happy if the road has a lot of camber.

WB9YZU is correct on the toe in specs for the later model. His figures are found in the 99 FSM, but in the '95 FSM and the old Haynes I used on the 87, the spec is 0 degrees. Although I've aligned all of them, it never occurred to me to look for a newer figure. I usually tried to err on the side of a tiny bit of toe in anyway, since the vehicles were used mostly in 2WD, and more likely to have a bit of play as they got older.

Well I pulled both diff covers tonight. They are both 3.55. But I did notice my front diff was very hard to turn by hand at the pinion. Then spun wheels and they seemed hard. I figured the brakes must be dragging. Pushed the calipers in a bit and everything loosened up. Pulled calipers off and slides were free. I had a huge ridge on the outside edge of the rotor so I figured I would just turn them. About halfway through turning them got a really bad chatter on the lathe. So will get some new rotors in the AM. These were warped pretty bad and had quite a taper.

Did brakes fix it?

Just got them put on this morning. Haven't got a chance to try it yet. Suppose to have some snow tonight here.

So got to do some driving in the snow today. I am not entirely sure its fixed. I seem to have a wine in 4x4, but only under acceleration. When I let off to coast it gets loose. Is there something in the t-case that would cause this? Both shafts felt fine in neutral.

Noise might still be gears.

Looseness on decel might be the drivetrain slowing down faster than the truck is on the snow. Happens to mine every winter. I hit the clutch/put it in neutral to let the wheels start spinning at road speed.