Clicking / popping from front axle during sharp turns

[fuse]

Pressure washing is death on components... Generally I prefer simple green and hose pressure.. my TJ really was the same story... 20,000 miles and
dude it was fried underneath.

I hear you. I wouldn't pressure wash my bikes. I use the gentle setting on the garden sprayer. But for the TJ I use the local self-serve car wash and keep some distance between the pressure nozzle and whatever I'm spraying. Up close, that thing is nasty, but after a foot or two it's much more gentle.

They would hit the mud and then hit it with the pressure washer... Then roll it into a dark damp garage to dry slowly.

Fortunately, everything is dry here in SoCal.

I know this sounds crazy... But if you play around with unit bearing you'll notice you can carefully remove the seals and pack that thing with grease. . I do the same thing on dirt bikes...grease it right inside the hub... Always remember... Anywhere you have grease is somewhere water can't go.

That is a great tip! I've been feeling like the unit bearings might be questionable so this is a good opportunity to inspect them. Even if they're doing OK, I could definitely repack them. Thanks!

 

[AndyG]

I hear you. I wouldn't pressure wash my bikes. I use the gentle setting on the garden sprayer. But for the TJ I use the local self-serve car wash and keep some distance between the pressure nozzle and whatever I'm spraying. Up close, that thing is nasty, but after a foot or two it's much more gentle.

Fortunately, everything is dry here in SoCal.

That is a great tip! I've been feeling like the unit bearings might be questionable so this is a good opportunity to inspect them. Even if they're doing OK, I could definitely repack them. Thanks!

Just be careful and don't mangle the seal I think there's actually two of them.. it may be brand-specific but it seemed like mine had a black seal that was sort of a dust boot and then the real seal under that was red. You really aren't going to hurt anything.... And I would rather have a bearing full of grease and a seal that isn't just dead perfect then a perfect seal with a dry bearing.

It is possible that there are different unit bearings in different sealed designs so always take what I say with a grain of salt.... The problem with being a Pioneer is you often get an arrow in the back.

 

[qslim]

Following @qslim's mention of the ChassisEars, I wrapped a Bluetooth headset in tissues to cut out some of the surrounding noise and duct taped it to the diff cover. Then used it to call myself on another phone. Made a couple three-point turns and could hear the popping out the window but not through the phone. Moved the headset to the steering knuckle and could hear the popping clearly through the phone.

Damn dude, that is some expeditionary work! Very creative.

There are alot of good writeups on changing u-joints on this forum... I'm not a fan of a press personally due to the risk of bending the yoke ears. Good ol' vice, hammer & muscle usually gets it done, I personally prefer an air hammer w/ a flat tip, makes it much easier but annoys the shit out of the neighbors.

 

[fuse]

OK. I've got some pretty clear results.


Everything there is pretty dry, but that's sort of a result of driving in the desert then power washing off all the dust. However, there may be a little grease at the ends of the u-joint caps.

Also, while I was feeling around the caps, I was able to wiggle the axle shaft a bit and feel some movement on the passenger-side u-joint. That's a pretty clear indication that there's a problem.


I tried that, but it didn't seem to do anything. Maybe the u-joint is far enough gone that a little spray lube isn't going to help.

Following @qslim's mention of the ChassisEars, I wrapped a Bluetooth headset in tissues to cut out some of the surrounding noise and duct taped it to the diff cover. Then used it to call myself on another phone. Made a couple three-point turns and could hear the popping out the window but not through the phone. Moved the headset to the steering knuckle and could hear the popping clearly through the phone.

So, we have a winner. Bad passenger-side u-joint. I'm ordering Spicer 5-760X replacements.

I dug up some of the online write-ups, and I guess I'm willing to go ahead and tackle this job on my own, even though I usually make a hash of anything that requires a press. Looks like Stu Olson has some good tips on removing and installing u-joints with a ball joint tool: https://www.stu-offroad.com/axle/ujoint1/u-joint-1.htm

Thanks everyone for the tips!

So the new u-joints went in without a hitch, and it turns out that was not the problem. I'm still getting the same noise, particularly when reversing direction while making a three-point turn.

I inspected and repacked both unit bearings while I was installing the u-joints, as @AndyG suggested, and it does seem that the passenger side bearing has seen more wear. It's possible that the PO had replaced the driver side bearing at some point since it looks a lot newer. I've suspected the passenger side bearing was going bad, so I've ordered a replacement set of unit bearings.

I'm going to say that the noise was from the hub. We'll see what happens when that replacement part comes in.

Would anyone who guessed the u-joints were the problem like to make another guess?

 

[AndyG]

So the new u-joints went in without a hitch, and it turns out that was not the problem. I'm still getting the same noise, particularly when reversing direction while making a three-point turn.

I inspected and repacked both unit bearings while I was installing the u-joints, as @AndyG suggested, and it does seem that the passenger side bearing has seen more wear. It's possible that the PO had replaced the driver side bearing at some point since it looks a lot newer. I've suspected the passenger side bearing was going bad, so I've ordered a replacement set of unit bearings.

I'm going to say that the noise was from the hub. We'll see what happens when that replacement part comes in.

Would anyone who guessed the u-joints were the problem like to make another guess?

I had a track bar mount do that once , drove me nuts . Could be a dry drag link end , etc. it’s amazing how hard it is to locate a noise on these can be , and the chassis is so accessible .

 

[fuse]

I had a track bar mount do that once , drove me nuts . Could be a dry drag link end , etc. it’s amazing how hard it is to locate a noise on these can be , and the chassis is so accessible .

I put a shot of grease into every fitting every time I work on the front end, so hopefully nothing is dry. But point taken — it could be something else.

I thought about it being something in the steering linkages or ball joints, but I can't get it to make the noise with just dry steering. So far, I've never heard the noise when the wheels weren't rolling. I don't suppose that rules anything out, but it makes me want to keep looking at the axle and hubs.

 

[BuildBreakRepeat]

I would suggest dropping the rear driveshaft, putting the front axle on jack stands, four high on the transfer case, and steer it left and right while it idles. You can walk around each part and visually inspect + listen to each part.

 

[fuse]

I would suggest dropping the rear driveshaft, putting the front axle on jack stands, four high on the transfer case, and steer it left and right while it idles. You can walk around each part and visually inspect + listen to each part.

That's the first thing I tried today, and I got no results. It seems to be something that happens under load, so spinning the wheels and turning the steering without any load doesn't do it.

I also tried shaking, prodding, twisting, and pushing the wheels, steering linkages, and knuckles with as much force as I could apply by hand and didn't get anything. Dry steering doesn't do anything either.

I did put in new unit bearings today, and that didn't affect the issue either. It did make the bad bearing sound go away, so there's that.

So it's back to square one and time for more diagnostics. Sharp turns seem to be most likely to produce the noise. Ball joints and the front diff are still some interesting suspects.

 

[AndyG]

Do your front springs have insulators at the top?

 

[fuse]

Do your front springs have insulators at the top?

Yep. And levelling spacers.

 

[BuildBreakRepeat]

Why not try the same experiment but have a helper work the brakes to test drag/load while turning? If that’s not it you can narrow it down to being weight influenced.

 

[fuse]

I cracked the front diff today to have a look, but I don't know enough to be able to tell if what I'm seeing is OK.

Does this look like a healthy Dana 30 to you guys?

Two things caught my eye, although they may be normal.

There seems to be some deformation on the outer edges of the side gears. Is that a normal shape for those gears?

Also, there seems to be some play in the spider gears. This video shows the movement if you look at the interface between the carrier and the spider gears. The sound in the video is just from the remaining gear oil.



Is that an acceptable amount of play for the spider gears?

 

[BuildBreakRepeat]

I cracked the front diff today to have a look, but I don't know enough to be able to tell if what I'm seeing is OK.

Does this look like a healthy Dana 30 to you guys?

View attachment 146156 View attachment 146157 View attachment 146159 View attachment 146158

Two things caught my eye, although they may be normal.

There seems to be some deformation on the outer edges of the side gears. Is that a normal shape for those gears?

Also, there seems to be some play in the spider gears. This video shows the movement if you look at the interface between the carrier and the spider gears. The sound in the video is just from the remaining gear oil.



Is that an acceptable amount of play for the spider gears?

The wear doesn’t look terrible, but that could be the clicking you are hearing

 

[fuse]

The wear doesn’t look terrible, but that could be the clicking you are hearing

Taking a closer look at the photos today, I noticed the signs of wear on the top land of the side gears. Those parts of the gears must be contacting the face of the spider gears. I think that's an indication that the gears are too worn to mesh properly.

I don't have any specific evidence to confirm it, but hopefully this is the cause of the clicking. Even if it's not, I think this diff needs service.

 

[fuse]

I swapped the spider gears in the front diff yesterday using a spare set from another axle. Replacement gears on the left, old gears from the Jeep on the right.

There seem to be some manufacturing differences between the two gear sets, but I did not like the look of the wear patterns on the side gears from my Jeep.

The swap went well, but sadly it did not fix the clicking sound. Now I'll have to take another look at the ball joints and the steering linkages. At least I'm getting a lot of preventative maintenance done and I'm getting really good at tearing down front axles.

 

[DEValken]

It is possible that there are different unit bearings in different sealed designs so always take what I say with a grain of salt.... The problem with being a Pioneer issue off and get arrows in the back.

What? I'm telling Blaine.

 

[fuse]

I think I got it this time. I had my wife do some very slow three point turns and dry steering while I was checking the ball joints to see if I could confirm whether that was the problem.

While I was doing that, it seemed that the clicking/popping was coming from behind the axle. I had a hand on the engine skid during some dry steering, and felt it pop. I've checked several times to make sure that skid has plenty of clearance, and I'm certain it's not contacting anything but the attachment points at the transfer case skid and frame.

My best theory is that the frame is flexing just enough during these sharp turns to tweak the skid's mounting brackets a little. And then there's just enough friction at the skid's mounting bolts that it pops when it shifts slightly.

So I loosened up the engine skid mounting bolts, gave it a good shake to make sure everything lined up, and tightened the bolts back up. And the noise is gone, at least for now. We'll see what happens when I can put some more miles on the Jeep.

Thanks to everyone who has helped so far, especially @AndyG and @xxdabroxx for suggesting it might be something totally strange.

 

[AndyG]

I had a popping noise in my front end that about drove me crazy... Turned out to be a dropped track bar mount where it squeezes the frame... You can almost be looking at something on one of these and you think it comes from somewhere else... There is so much steel in these things that it makes it hard to isolate things.