Steering Issue - choppy steering wheel return

96 XJ, 4.0, NP231, 290,000 miles

The last two times I've used 4wd (only momentarily) I've noticed that after I return to 2wd that the steering doesn't feel right. When turning the wheel the problem is barely noticeable, but as the wheel is allowed to return to a centered position it feels like the power steering is cutting in and out. The wheel returns to center with a choppy feeling to it. At a stop I can move the steering wheel as far as it will go in either direction and I don't get the choppy feeling. It only happens when moving. It goes away after a short time and I have never experienced it without using 4wd first.

It felt like air in the PS system maybe so I worked the steering wheel back and forth for a little while. The problem seemed to be gone for the most part after I did that.

I had a pretty bad PS leak for a while. Three bottles of Lucas PS Stop Leak has almost completely sealed it. I can see how air could get in the system with a leak. What I can't understand is why this only happens after I use 4wd. Has anyone else experienced this?

Steering wheel wiggle when returning to straight ahead, is probably bad u-joints in the axle shafts.

Does it go away? Bad ujoints would mean you always have this problem, which is possible. But it sounds like it stops, so the 4wd may nit be disengaging right away causing your slight bind. What kind of surface does it do it on?

trippled said:

Does it go away? Bad ujoints would mean you always have this problem, which is possible. But it sounds like it stops, so the 4wd may nit be disengaging right away causing your slight bind. What kind of surface does it do it on?

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I thought the same thing about the u-joints but I checked them anyway. I jacked the front end up just now and watched the u-joints as I turned the tires by hand. There was no slop/play in them. No ticking or grinding noises either.

I'm getting the choppy steering on pavement, more noticeable in parking lots or at slow speeds. The first time it happened was after I put it in 4 low to back down an extremely steep/rough rock driveway. I normally wouldn't use the 4wd on a dry surface but with all the ruts and the extreme angle of the drive I was afraid I would slide off where I don't have anti-lock brakes. I only went in a straight line though, no turning. I drove about seven miles back to the pizza store I work at and parked. I checked the PS fluid thinking it might be low but it was fine. I didn't notice the issue again until today.

Today I was coming up a very steep gravel back road. I had to get over into a washed out portion of the road for an oncoming vehicle. I had to throw it in 4 high to get out of the loose stuff and a ditch. I used the 4wd for literally three feet at most and immediately the choppy steering came back (in gravel this time). I drove three miles to town with the choppy steering and pulled over in a parking lot. I put it in reverse and backed up 15-20 feet to make sure the 4wd had disengaged. That didn't help anything so I drove it a little further then stopped and turned the steering wheel all the way in either direction a bunch of times and that seemed to fix it.

It doesn't feel like it is staying in 4wd but I could be wrong. I've noticed that when using 4wd it is significantly harder to turn, especially if I get on a dry surface in 4wd. It isn't the same binding feeling that you get from that.
(I'm aware that you shouldn't use part time 4wd on dry surfaces. :nono
It feels more like a fluctuation in the power steering fluid pressure.

I've never felt the choppy steering while using 4wd either, but I haven't used it for a prolonged period in several months.

You have bad axle U-joints,Spin the tire by hand,,forward and backward while watching the joint.You will see it move. Spinning it in one direction only will hide the problem.

Wayne Sihler said:

You have bad axle U-joints,Spin the tire by hand,,forward and backward while watching the joint.You will see it move. Spinning it in one direction only will hide the problem.

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That's what I did, forward and backward - no slop. I even gripped the axle with one hand to see if I could get the tire to turn back and forth a little without the axle turning. It's solid.

One of the bearing caps could be seized to the trunion. It probably won't be apparent without removal of the wheelbearing/axle assy. The other three caps are probably masking any movement. My $.02 axle u-joints.

four_shot said:

One of the bearing caps could be seized to the trunion. It probably won't be apparent without removal of the wheelbearing/axle assy. The other three caps are probably masking any movement. My $.02 axle u-joints.

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Quite possible I'm sure.

Better yet, Jack up the front and turn the wheels to the far left or right. With the steering turned try to spin the wheels by hand. If it binds theres a bad joint. Could be seized without any play or noise

trippled said:

Better yet, Jack up the front and turn the wheels to the far left or right. With the steering turned try to spin the wheels by hand. If it binds theres a bad joint. Could be seized without any play or noise

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I'm going to go ahead and go with the popular opinion here that the u-joints are bad without any further testing. It's still hard for me to comprehend why I don't always have the problem but I trust the experience of the folks here. At $30 each for new Spicer u-joints, I really have no excuse not to replace my original (guessing) equipment. I may even do this myself if I can find a friend with a pneumatic wrench.

I appreciate everyone's help.

Joe

four_shot said:

One of the bearing caps could be seized to the trunion. It probably won't be apparent without removal of the wheelbearing/axle assy. The other three caps are probably masking any movement. My $.02 axle u-joints.

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four_shot nailed it. After removing the tire and the tie rod, it was apparent that half of the passenger side u-joint was good and the other half was bad. The rotor was easy to move left to right in one position, but rotate the joint 1/4 turn and everything got stiff. I didn't get a chance to inspect the old u-joint because my mech cut it out with a torch.

I went with the Precision u-joints that were available at the local NAPA store.