I sure could use some help. My 1991 Land Cruiser (180K miles) has had a driveline clunk since before I bought it 6 years ago. After reading posts on this site I've tried several cures, like lubing the splined shaft, new lube in the front and rear diffs, nothing seemed to work. It always clunks when shifting from drive to reverse and reverse to drive and it has a clunk most times when letting off the gas or putting on the gas at slower speeds. I can't make out exactly where the clunk is but it seems like in the mid or rear area of the drivetrain. There is apparent slop in the driveshaft going into the rear diff, no apparent slop in any of the u-joints (which I've also lubed). If I knew for sure it was the rear diff I might spend the money to replace the whole thing but I'm not sure and I'm getting tired of fixing the wrong thing. I'm also getting older and making repairs is not as easy as it used to be. I'd love it if someone near me knew enough to diagnose and repair the issue but the dealership can't even tune the 80 up and I have no confidence in any of the local shops to know much more about this old vehicle. Can I get some advice, either about the possibility of the slop in the rear diff being the cause or maybe even a competent technician within a couple hundred miles of me? I live in the metro Detroit area. Maybe even a savvy DIY tech from IH8MUD is within driving distance and could use a project and some income? I love this vehicle and want to keep it but I've grown tired and worried about the clunk. Thanks, Bob Nancarrow (nanthor@hotmail.com)
80 series driveline clunk repair? (1 Viewer)
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Hopefully you can get a knowledgeable person to take a personal look at it, but in general some driveline clunk is normal. If you can't find a problem, maybe you don't have one.
4LowandSlow
SILVER Star
I had the same clunk your talking about, I replaced my 300k upper control arm bushings and haven't felt it since, check those to see if there still good, You want to look for dry rot in the bushing. A little driveline clunk is normal btw. Possibly could be a transmission mount? Hope this helps!
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Thanks so far for the suggestions, I will check to upper control arm bushings. I have read that there are any number of things that could be the cause. Also, I wouldn't call it a little driveline clunk, it is serious enough to prevent a sale, I am sure. Feels like something is going to break soon if it continues and the only reason it is not worse is because I think I keep the clunk a little less by the way I drive and operate the car, if that makes sense. I suspect if a non-fj80 clunk driver were to drive it the clunk would be louder and more dramatic, feel worse. Thanks, Bob.
Realize that the 91-92 LC's do not have a visciuv coupler in the transfer case to "absorb" the clunk.
Drive line clunk is actually normal on those.
You've only got 180K on it and it should be OK.
Yes, it's worth making sure it's not something serious.
The first thing I would probably check on those would be the front drive flanges, as they wear and loosen up with a lot of pavement city driving.
@jonheld is the guru on the 91-92 version and he will usually reply if called, as I have done.
Make sure you are checking the drive line and ujoints with the drive line UNLOADED meaning transmission in neutral, tires chocked, no parking brake, level surface.
Check DS up/down, left/right, and rotationally. You should see about 1/2"-3/4" rotation at the hub. There Should be NO movement in the ujoints. You should grease them this way as well.
Drive line clunk is actually normal on those.
You've only got 180K on it and it should be OK.
Yes, it's worth making sure it's not something serious.
The first thing I would probably check on those would be the front drive flanges, as they wear and loosen up with a lot of pavement city driving.
@jonheld is the guru on the 91-92 version and he will usually reply if called, as I have done.
Make sure you are checking the drive line and ujoints with the drive line UNLOADED meaning transmission in neutral, tires chocked, no parking brake, level surface.
Check DS up/down, left/right, and rotationally. You should see about 1/2"-3/4" rotation at the hub. There Should be NO movement in the ujoints. You should grease them this way as well.
There are probably 100+ posts on "driveline clunk" relating to US spec FJ80s.
As stated above, some driveline slop is normal and you will have to live with that. It is a 27 year old truck, not a modern sports sedan.
That being said, I will repeat what was previously stated. Make sure there is no axial or lateral play in the 2 drive shaft slip yolks. Make sure there is no play in the 4 universal joints.
Front drive flanges can be an issue on the older trucks if neglected, but I have changed mine along with outer shafts and it made no difference.
The front will have more slop than the rear as there are more interfaces. So when you're under the truck with the wheels chocked and the transfer case in neutral, it is normal to see more rotational play in the front than the rear when you're rotating drive shafts by hand.
Unless this truck has been neglected, it is unlikely something sinister. An easy way to localize is to remove 1 drive shaft, lock the center differential using the dash button, and drive around for a while. This will also give you a chance to closely inspect the drive shafts for play and/or notches in movement.
As stated above, some driveline slop is normal and you will have to live with that. It is a 27 year old truck, not a modern sports sedan.
That being said, I will repeat what was previously stated. Make sure there is no axial or lateral play in the 2 drive shaft slip yolks. Make sure there is no play in the 4 universal joints.
Front drive flanges can be an issue on the older trucks if neglected, but I have changed mine along with outer shafts and it made no difference.
The front will have more slop than the rear as there are more interfaces. So when you're under the truck with the wheels chocked and the transfer case in neutral, it is normal to see more rotational play in the front than the rear when you're rotating drive shafts by hand.
Unless this truck has been neglected, it is unlikely something sinister. An easy way to localize is to remove 1 drive shaft, lock the center differential using the dash button, and drive around for a while. This will also give you a chance to closely inspect the drive shafts for play and/or notches in movement.
I've owned my 91 since 1999, and my 92 since 2008.
Clunk clunk clunk clunk down the road I go...
Clunk clunk clunk clunk down the road I go...
This is soooooo totally normal.
Of course check what jonheld and others have mentioned, but at some point you really just have to embrace the clunk.
Sometimes when I'm driving along and get bored, I keep letting off and putting on the gas just to amuse myself. (Not kidding.)
This is soooooo totally normal.
Of course check what jonheld and others have mentioned, but at some point you really just have to embrace the clunk.
Sometimes when I'm driving along and get bored, I keep letting off and putting on the gas just to amuse myself. (Not kidding.)
I used to do that with my old Chevy! Ha!
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Great comments, I really appreciate everyone taking the time to help. I'll check everything mentioned in hopes that I can make it a bit less noticeable but I won't be OCD about the clunk. I have lived with it for about 6 years of ownership now and it doesn't bother me too much. I just worry that when my son wants to borrow the truck he might make things worse if the clunk is something that is too worn. Today I was driving it and while going down a hill I took my foot off the gas and got a real significant clunk. Add that to the times it occurs most often. Thanks again, time to get under there now. Bob.
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Also, I apologize for even starting this thread. I know there are tons of threads about the clunk, I've searched them, but there is so much information that I was getting confused and thought that maybe I could get some specific info by giving the specific symptoms I was having. I'm really ecstatic that some knowledgeable FJ80 fellows gave me some things to look for. Thank you, thank you, Bob.
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Well, here's an update. Seems like the upper and lower control arms are rock solid and what I can see of the bushings look good. Trying to move everything else, it all seems really solid. There is a tiny amount of play in the smaller crossover bar links in the rear but I think that's not an issue. All the U-joints seem tight without play, the shafts don't have any rotational play at the splines and just a fraction of longitudinal movement. No sideways or up/down movement at any of the driveshaft hubs where they come out of differentials or the transfer case. While there is a little rotational play in the rear driveshaft there is a LOT of rotational play in the front driveshaft, don't know how many degrees but at least an inch if it was linear and the hub I'm basing it on is about 3-4 inches in diameter. I'm tempted to ask my son to move the selector from drive to reverse while I'm under the car to find out if I can tell if the clunk is coming from the front driveshaft play, either in the front diff or the transfer case but I was a firefighter for many years and saw some bad results when people did that sort of DIY thing. Maybe if I used the house and a car to keep the truck from moving but I'd be a little reluctant even at that. Any suggestions? Does excess play in the driveshafts ever equate to the clunk?
I'll probably next do what jonheld suggested about isolating the shafts. Thanks, Bob.
I'll probably next do what jonheld suggested about isolating the shafts. Thanks, Bob.
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Yes, but I don't send discs out anymore. I set it up do you can download.
All rotational driveline items must have a degree of 'freeplay' in them otherwise things sieze up. Clunk in the driveline is the sum total of all elements of freeplay and it starts right from the clutch where the input shaft to the gearbox fits into the clutchplate (for manuals at least). There's freeplay in the gearbox, the transfer case, the tailshaft(s), the diff(s), and the front CV joints (those things some people call rzeppa joints or birfs) along with the driveshafts where they fit into the diff centres. If the wheel bearings are not pre-loaded correctly there's more play there, and same with the kingpin bearings if they are not in good shape. It all adds up.
Some elements of the freeplay are easy to fix - some aren't.
Some elements of the freeplay are easy to fix - some aren't.
COYS
SILVER Star
Even with a full sus refresh with oem bushings, new tie rods, double cardan front, and full front and rear axle rebuild with only the best made in jpn parts, I had a clunk upon throttle app at say traffic lights.
Got a new rear driveshaft. Now it’s like a Tesla. Zero clunk. Still plenty of emissions though.
You can go cheaper with just oem ujoints. I reduced my risk by eliminating variables.
Got a new rear driveshaft. Now it’s like a Tesla. Zero clunk. Still plenty of emissions though.
You can go cheaper with just oem ujoints. I reduced my risk by eliminating variables.
You also got new splines on the drive shaft.
I also fitted a brand new genuine rear shaft recently - for mine it was a 37110-60450. New slip joints have very little rotational freeplay but they still must have a very small amount otherwise the slip joint cannot function.
I'm just about to replace the front shaft as well - it had large freeplay in the slip joint but as part-time 4wd hardly ever gets used.
Steering can and often does have a lot of freeplay too but that's a different story altogether.
I'm just about to replace the front shaft as well - it had large freeplay in the slip joint but as part-time 4wd hardly ever gets used.
Steering can and often does have a lot of freeplay too but that's a different story altogether.
