[newdad1]

I need any help possible on this one.
This is what I have;
My daily driver is a 1998 Jeep Cherokee 4.0L 4wd 4speed automatic 166,000 miles VIN:1J4FJ68S4WL173795

This is what it is doing;
Making a popping noise most offen when I turn left or right after initially starting to move. I can get the jeep to make the noise by turning the wheel to the left and moving slowly fwd. I can get it to make the popping noise again by putting it in reverse and keeping the wheels turned to the left move slowly backward.

The vehicle is not in 4wd when it makes this popping noise
When I do put the vehicle in 4wd it runs fine as long as I don't go around any sharp turns. There are 2 4wd settings; 4H, and 4L. There is another setting, 2H which is what I run in all the time.I can do 60mph in heavy rain with it in 4H with no problem. 4L is for going up hills at low speed which I don't do.

I just put new synthetic gear oil (140W grey bottle by SuperTech I believe)in both front and rear differentials. When I pulled the front cover off of the differential, I did not see anything obvious but then I wasn't looking for anything specific.
Two people have said the noise seems to be coming from the front differential. The front axles have universal joints not CVJ. They looked OK.

My questions are;
How can the noise be coming from the front differential if I don't have it in 4WD?
If I take the front differential cover back off to inspect, what should I be looking for that would make this noise?
What else should I check for?

You guys have saved me lots of $$$ already from previous posts.

As always, any and all responses are greatly appreciated

Thanks,
Robert D.

[Chevrolet4x4s]

Do you have any shakes or death wobbles?
Shane

[tnsmith10]

give a closer look at the u-joints in the front drive axles, not just visibly, but also see if theres any play. another thing to look for is ball joints, upper and lower, front wheel bearings, and the front sway bar. does it only pop when its rolling? have you made sure that the hubs are unlocking/unlocked when you bring it out of 4wd? you do know that you need to back up about 5 feet or so after disengaging the 4wd so it will unlock the hubs? and last, does the front driveshaft still turn after you take it out of 4wd?

[newdad1]

All of the following have been replaced with new parts within the last couple of months:
-Ball joints upper and lower both sides
-Sway bar bushings and end links and bushings both sides
-Steering box
-lower control arm bushings both sides


I have a seperate lever next to the shifter that I pull back to put it in 4WD. I did not know I had to back up after taking it out of 4WD to totally disengage.

[newdad1]

Oh yeah, it only pops when the vehicle is moving. I am not sure what a death wobble is? When it pops I can't feel any unusual shakes. I will check the other stuff you have suggested

[prostreet6t9]

You don't have locking hubs correct? Take a good look at the inner axle u-joints. See if there is any sign of rust around the u-joint caps. Sounds like it may be a bad inner axle u-joint.

[newdad1]

That is correct. I do not have locking hubs. When I put it in 4WD, both axles/u-joints for the left and right front wheels turn. When I take it out of 4WD, both axles/u-joints for the left and right front wheels still continue to turn.
I will take a closer look at the u-joints, wheel bearings today.

[tnsmith10]

Originally Posted by newdad1

That is correct. I do not have locking hubs. When I put it in 4WD, both axles/u-joints for the left and right front wheels turn. When I take it out of 4WD, both axles/u-joints for the left and right front wheels still continue to turn.
I will take a closer look at the u-joints, wheel bearings today.

that means that they are automatic hubs. they are not supposed to engage till the t-case engages the front driveshaft, then they will engage. thats why you have to back up to release them...
thats why in my previous post, that i asked if the driveshaft still turns after putting the vehicle back into 4x2. the problem could actually be in the t-case, and not the hubs.
i have replaced the hubs on several, because they get stuck engaged

[eloc431962]

I am not sure about 98 jeeps, But some 4x4s the axles turn when out of 4 wheel drive, it sounds like a axle joint , or if your jeep has the cv joint type axles it will be the cv joint in the axle if it has cv type check and see if the boot is tore up or ripped and got dirt and road grime in it and wore it out. either way what you are describing sounds like a axle joint be it a regular u-joint or a cv type joint. JMO. Cole

[newdad1]

The wheel bearings are ok. I did not see any unusual movement from the universal joints in the front axles. I only have universal joints at the spindle end, not going into the differential. I assume that is what you meant by inner ujoint.

The other thing that may be significant is that the front axles and front drive shaft are turning all the time. It does not matter if it is in 4X4 or 4X2.

Just to make sure. I put the vehicle in 4X4 and watched both front axles and the front driveshaft turn. I had a friend drive while I watched. They took it out of 4X4, and then backed up 5 to 15 feet. I then looked underneath the vehicle again and saw the driveshaft and both front axles turning. Does this mean anything?

[prostreet6t9]

Originally Posted by eloc431962

I am not sure about 98 jeeps, But some 4x4s the axles turn when out of 4 wheel drive, it sounds like a axle joint , or if your jeep has the cv joint type axles it will be the cv joint in the axle if it has cv type check and see if the boot is tore up or ripped and got dirt and road grime in it and wore it out. either way what you are describing sounds like a axle joint be it a regular u-joint or a cv type joint. JMO. Cole

You're correct.That year jeep should have a live spindle front end and have the 1 piece front wheel Brg's that bolt into the knuckle. If it's that style there is NO automatic hubs and the inner axle will alway's rotate.

It could also be the Booted CV style also and a torn boot would cause that problem as you stated. The CV booted one's are not as common but it will stll rotate at all time's.

[prostreet6t9]

Originally Posted by newdad1

The wheel bearings are ok. I did not see any unusual movement from the universal joints in the front axles. I only have universal joints at the spindle end, not going into the differential. I assume that is what you meant by inner ujoint.

The other thing that may be significant is that the front axles and front drive shaft are turning all the time. It does not matter if it is in 4X4 or 4X2.

Just to make sure. I put the vehicle in 4X4 and watched both front axles and the front driveshaft turn. I had a friend drive while I watched. They took it out of 4X4, and then backed up 5 to 15 feet. I then looked underneath the vehicle again and saw the driveshaft and both front axles turning. Does this mean anything?

Do you see any rust around the U-Joint cap's? If the joint is froze up,you will not get any play out of it.

[T-bucket23]

This is a very common issue, frozen universal joints in the front axles. There wont be play because they are frozen. You will see rust where the cross goes into the cups. Usually the noise is more prevalent while backing up.

[eloc431962]

This came to me today while at work, If your drive-shaft and axles are turning while out of 4x4 then it is more than likely that your actuator has gone bad, Hoping that it's not the t/c. Had this happen on a 89 jeep wrangler, assuming they are still the same in 98 ? but if they are the actuator is mounted on the passenger side down on the front housing, If this goes out you either cant get it in 4x4 or you can't get it out but sometimes it might work in between the actuator has the vacum line running to it and its what engages the 4x4.JMO It could also be one of the lines on top of the T/C cracked or came off or the line on the actuator . hope this helps. Cole

[newdad1]

Thanks for all the responses.
This is what I have found out. I jacked the front of the jeep up and put the front end(front tires off the ground) up on jackstands. I started the jeep and turned the wheel all the way to the left, where I can manually get it to make the popping noise when I slowly drive it forward or reverse. I got underneath and turned the front tire forward and backwards all the while watching the universal joint within the yoke. I did not hear any popping noise. I did notice some surface rust on the universal joint caps after I scraped some of the road grime off with a small screw driver. On the driver side there is a plastic cover that is suppose to be butted up against the axle housing. It is located close to the ball joint right where the axle comes out of the axle housing. It actually goes around the axle. The plastic cover was not flush with the housing. There was approximately a 1/4 inch gap. I shined a flashlight inside and could see rust on the axle shaft. It was also a little wet where the axle comes out of the housing. The drivers side universal joint had a pin-hole size grease fitting that was covered with crap. Everything looked and sounded like it was working correctly with the exception of what I described above.

The passenger side did not have a grease fitting. Its plasic cover was butted up against the axle housing. I did not see any rust on the axle on that side or any wetness coming out of the axle housing. There was also some surface rust on the caps and joints on that side also but when I turned the wheel forward and backward, it also appeared the work ok.

Sorry for being so long winded on this. I am ready to fix this now.
What should I do now other than bringing it to a shop?

One thing I have not mentioned. This jeep was a sheriffs vehicle a year or so go. I have only had it for a few months and put abourt 20K miles on it.