Learning about the "Clunk" - New member- First post!

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I just bought my first 100 series this past weekend. It's a 2000 LX470 with 183,000 miles, lifted, and running 34" tires. I have a ton to learn about these and I'm looking forward to digging in to the wealth of knowledge from you all. My first question is about the drivline "clunk". It seems many are trying, greasing the axle, replacing diff bushings, etc...... and a lot of the time, it helps, but doesn't solve the issue completely. So my first question is simply this: Is this "clunk" acutually damaging anything? Or is it just simply annoying? It doesn't bother me enough to start going down a rabbit hole to solve it, if it's basically harmless. 2nd part to the question is this. Does the "Clunk" happen to those with stock setups? Or just the big tire/lifted guys? Thanks for your input in advance.

IMG_E0574.jpg
 
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Nice looking ride!

The way I look at it is a question of mechanical wear. The clunk is two parts of metal hitting against one another reasonably hard making the noise… over time that cannot be good. If you read through a lot of the fixes for the clunk, most appear to fall in the maintenance or warm parts… either under lubed driveline components or bushings somewhere not holding everything in place.

At some point are there reminisced returns to trying to find an extra elusive clunk, sure… that said, I’d definitely go through the low hanging fruit before I just gave up on a solution.

I am sure longer term owners will have input, but as someone also new and read through a bunch of threads, this is how I am approaching it.

Good luck!
 
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Mine is 100% stock setup and was clunking pretty bad. I greased the u-joints and slip joints and didn't really notice any difference. I just finished replacing the front bushing on the front diff and that cured about 90% of it. There still seems to be a small clunk coming from the rear but it's barely noticeable at this point. I also checked my cv axle splines and they were in good shape but I know they can also contribute to the problem. You can go to harbor freight and purchase the chisel set for about $15. With that and a 2lb sledge hammer I was able to do the job in under an hour. A ball joint press makes pretty quick work of getting the new one in. There are a couple videos online of the process.
 
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Mine is 100% stock setup and was clunking pretty bad. I greased the u-joints and slip joints and didn't really notice any difference. I just finished replacing the front bushing on the front diff and that cured about 90% of it. There still seems to be a small clunk coming from the rear but it's barely noticeable at this point. I also checked my cv axle splines and they were in good shape but I know they can also contribute to the problem. You can go to harbor freight and purchase the chisel set for about $15. With that and a 2lb sledge hammer I was able to do the job in under an hour. A ball joint press makes pretty quick work of getting the new one in. There are a couple videos online of the process.
Thanks for this info. I'll for sure tackle the front diff job for the potential of a 90% improvement.
 
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Myself and many others have chased it with minimal success. Sure you should be greasing your driveline and making sure your CVS and hub flanges aren't worn. But otherwise don't start throwing parts at it. I've replaced bushings and just about everything I can get my hands on, it didn't help. Many years later, it still clunks, and I still just try to ignore it.

When you grease the slip yoke in your drive shaft, keep an eye on how much the driveshaft is moving. It took me many rounds of grease to get the front driveshaft to actually pass grease around the seal and not just extend the shaft.

A fully greased slip yoke and gentle rolling shifts into gear are my band-aid fixes to dealing with the clunk.

If you engage your center diff and the clunk goes away, I am convinced the slop is just in the the transfer case / differentials.
 
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If you engage your center diff and the clunk goes away, I am convinced the slop is just in the the transfer case / differentials.
Thank you for that info. Not sure what this means: "If you engage your center diff and the clunk goes away, I am convinced the slop is just in the the transfer case / differentials.
 

saucebox

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To counter Mike's experience—new diff bushings did the majority of cleaning mine up, and new bushings in the rear control arms (I just replaced all the arms with adjustable arms, to clean up the pinion angle) did the rest. Prior to trying to find the problem, I'd already done CVs and new drive flanges.

Then I cut it all off anyway 🙄. But for a year or so, zero clunk.

If you've got that much play in the differentials, future you will have at least one bad day. I guess you could drop a driveshaft and feel the pinion flange for play. One at a time, of course, so you don't run yourself over. An acceptable amount of play is in the thousandths of an inch—like .006 to .012 or so. Worn gear sets might creep those numbers up, but I'm doubting you could gain a significant driveline clunks in the diffs without also gaining significant driveline problems. (I do not know this for a fact, just a hunch.)
 
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Mine is 100% stock setup and was clunking pretty bad. I greased the u-joints and slip joints and didn't really notice any difference. I just finished replacing the front bushing on the front diff and that cured about 90% of it. There still seems to be a small clunk coming from the rear but it's barely noticeable at this point. I also checked my cv axle splines and they were in good shape but I know they can also contribute to the problem. You can go to harbor freight and purchase the chisel set for about $15. With that and a 2lb sledge hammer I was able to do the job in under an hour. A ball joint press makes pretty quick work of getting the new one in. There are a couple videos online of the process.
This was my experience as well.
 
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To counter Mike's experience—new diff bushings did the majority of cleaning mine up, and new bushings in the rear control arms (I just replaced all the arms with adjustable arms, to clean up the pinion angle) did the rest. Prior to trying to find the problem, I'd already done CVs and new drive flanges.

Then I cut it all off anyway 🙄. But for a year or so, zero clunk.

If you've got that much play in the differentials, future you will have at least one bad day. I guess you could drop a driveshaft and feel the pinion flange for play. One at a time, of course, so you don't run yourself over. An acceptable amount of play is in the thousandths of an inch—like .006 to .012 or so. Worn gear sets might creep those numbers up, but I'm doubting you could gain a significant driveline clunks in the diffs without also gaining significant driveline problems. (I do not know this for a fact, just a hunch.
Dang, yeah I wasn't as lucky.

Does my logic make sense that when you press the center diff, if the clunk goes away, it must be something internal? If the clunk goes away with the diff locked I can't see how stuff like bushings or control arms could have any different reactions.
 

jLB

May be in need of a 12 step LC/LX program.
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Our 99 LX had a horrible driveline clunk when we purchased it. It sounded and felt like the transfer case was going to jump through the floorboard. The process of replacing CV axles & drive flanges, along with replacing all the typical “rubber bits” (control arm bushings, front diff mounts, engine mounts) has eliminated ~98% of the driveline clunk. There is still a very minor clunk (more than our lesser mile 100 series), which can be somewhat addressed by greasing the slip yokes. Mildly irritating to me, but not so much that a passenger starts trying to figure out who just rear ended us.
 
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I just bought my first 100 series this past weekend. It's a 2000 LX470 with 183,000 miles, lifted, and running 34" tires. I have a ton to learn about these and I'm looking forward to digging in to the wealth of knowledge from you all. My first question is about the drivline "clunk". It seems many are trying, greasing the axle, replacing diff bushings, etc...... and a lot of the time, it helps, but doesn't solve the issue completely. So my first question is simply this: Is this "clunk" acutually damaging anything? Or is it just simply annoying? It doesn't bother me enough to start going down a rabbit hole to solve it, if it's basically harmless. 2nd part to the question is this. Does the "Clunk" happen to those with stock setups? Or just the big tire/lifted guys? Thanks for your input in advance.

View attachment 3071273

Mine is solved, the only "clunk" left is when shifting from park into drive, but almost every truck has some version of this once it gets older, seems to be more in the transmission, or diff gears, or transfer case, who knows. The taking off from stop, accelerating, and changing gear clunk that was driving me and drives others nuts can all be solved. Just a matter of how many bushings, u joints, and other drive line and suspension components you are willing to replace. I've replaced everything, and it feels like it.
 
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I'll replace the front diff bushing next weekend and see. That'll probably be the extent of what I'll be willing to do. Greasing of the axle softened the clunk, but didn't solve it.
 
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I'll replace the front diff bushing next weekend and see. That'll probably be the extent of what I'll be willing to do. Greasing of the axle softened the clunk, but didn't solve it.
Search here... there's a long thread specific to the driveline clunk.

Before you go to the expense of the bushings, put a video camera under the car where it can see the differential while you create the clunk. If the diff bushings are part of the problem (and it's often multiple things contributing a piece), you'll see the diff "jump" a little bit. Two of the three diff bushings are somewhat easy to replace (other than the fact they're torqued to something like 135 ft-lbs and are difficult to get off), but the front bushing will take some effort to pry out. Chowcares did a YouTube video of replacing this one that will be helpful. The front bushing is the cheapest to replace but will take the most effort.
 

saucebox

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Search here... there's a long thread specific to the driveline clunk.

Before you go to the expense of the bushings, put a video camera under the car where it can see the differential while you create the clunk. If the diff bushings are part of the problem (and it's often multiple things contributing a piece), you'll see the diff "jump" a little bit. Two of the three diff bushings are somewhat easy to replace (other than the fact they're torqued to something like 135 ft-lbs and are difficult to get off), but the front bushing will take some effort to pry out. Chowcares did a YouTube video of replacing this one that will be helpful. The front bushing is the cheapest to replace but will take the most effort.

Ah, that's smart. I laid under the car while my wife considered the life insurance payout.
 
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Ah, that's smart. I laid under the car while my wife considered the life insurance payout.
That didn't come into play at my house. I think the only piece of my dad's advice I've followed was to never be worth more dead than alive. He probably meant I should strive to be productive and valued by those around me, yada yada yada, but I interpreted it as never buy life insurance.
 

Dparo

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I was driving across country last year and I was in a rest area for a quick nap to get right back on the road. After about 20 minutes of having the vehicle off I felt a thump, thought someone bumped into me. I got out and looked around but I was the only one there.

After it happened a couple more times that trip I kind of wondered if it was the driveline thump from relaxing from being under load. Anyone ever have this?
 
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I did the install today on the front diff bushing. Not the magical solution to the clunk, but it is better. It needed to be replaced anyhow. The old one was torn and brittle. It was way easier to get out than I expected, but way harder to get in than I expected.
 

jLB

May be in need of a 12 step LC/LX program.
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I did the install today on the front diff bushing. Not the magical solution to the clunk, but it is better. It needed to be replaced anyhow. The old one was torn and brittle. It was way easier to get out than I expected, but way harder to get in than I expected.

All front diff bushings, or “the easy one”?

CV axles & drive flanges are the other “big one”, after replacing “all” of the front diff bushings.
 
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All front diff bushings, or “the easy one”?

CV axles & drive flanges are the other “big one”, after replacing “all” of the front diff bushings.
Just the very front one. I guess that's "the easy one". Will get to them all eventually.
 

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