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Again I think we are way over-thinking this. There are needle bearings in each of the four caps. These can become worn. Sometimes they have fallen out that could cause the joint to be loose. I’ve on,y done a couple cars and usually the bearing don’t look very good after a few hundred thousand miles. They are cheap though and only take a couple hours to replace.

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That’s interesting. I’ve always tested them just by twisting method. My truck has a similar unexplained clunk, and all u-joints pass the twist test. So wondering if maybe it has a hidden u-joint problem? If twisting isn’t diagnostic, is there a method that is?

In rear drive cars u joint clunks were fairly common and you just replace the joint. But this is more of a rap than a clunk so hopefully it is just the $20 joint and not the rear end. The joints have bearings in that wear out. You can do it yourself if you like crawling under the car, have some sockets and a big vice, or just have any shop do it and see if the noise goes away.

I found this video, I had the sound OFF so no idea what he said but the video shows what to do once the rear tires are off the ground… Keep in mind any play is bad and any one or more of the u-joint cups on the cross could be bad…

It’s not that difficult to take a guess it is bad & replace a single u-joint. But my truck’s rear driveshaft has a lot of u-joints. It would be a pretty big chore to replace all of them just b/c one of them might be faulty.

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Also had a guy who worked for me polevault his new (to him) Lightning during a (street) race. He cleared the guard rail.

This is what the clunk sounds like. I took it to another mechanic who didn’t know what it was, but said I might want to take it to transmission place. II’ve noticed that if I pause in neutral before shifting into drive that there is minimal or no clunk. I also took it to a Toyota who also didn’t know what it was, but didn’t think it was an issue.

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Individual U-joints shouldn’t have any noticeable play when twisting on them hands on each side/ The overall linkage from the transmission output, through the driveshaft, then differential, and then axle shaft will normally have some play though. I did that measurement on my truck’s rear wheels recently, around 4 degrees of play at the wheel as I recall.

When a U-joint goes bad, you cannot tell by twisting the driveshaft. A bad U-joint can do damage to the rest of the drive train, especially on 4wd vehicles. I had one go bad on my Silverado that barely made a clunk, but it cracked the adapter case between the transmission and the transfer case. That was no fun to replace. I just replaced the rear U-joint again after about 60k miles, the needle baring were shot under two of the caps.

You beat me to it. When I was in elementary school, the father of one of my classmates decided that he could ignore the ominous sounds of a u-joint that was on its last legs. When the front u-joint failed–at high speed–on the NJ Turnpike, his car essentially pole-vaulted.

It could just be my bad eyes but I thought I saw movement in the u-joint… It would be better to jack the back tires up off the ground on stands and put the vehicle in neutral and move the driveshaft with your hands…

In addition to the cost of the repairs, he had to pay for a tow, and a few weeks later he got a bill in the mail from the Turnpike Authority for the cost of repairing the damage that he had caused to the roadway. IIRC, he had to pony-up more for the road repair than he paid for the u-joint replacement.

It could be the back lash in the rear end or even very low on gear lube… Try calling around and asking shops if they do driveline repairs before you take it to them…

I might want to take it to transmission place. … … I also took it to a Toyota who also didn’t know what it was, but didn’t think it was an issue.

Many moons ago driving to work in Minneapolis, there was a Chrysler with the rear end up in the air, held in place by the broken drive shaft. Just like a pole vault. I guess have a rope along so you can repel to the ground. A lot of cars have a brace across in case the joint breaks, but yeah play in the shaft means shot bearings.

Back to post 10 with the video showing a worn u joint. They don’t have to be that loose though to clunk. Not understanding any connection to steering?

I have a 2007 Sequoia with 173k miles. There’s a clunk when shifting into drive or reverse. Two mechanics have said it’s the u joint, but don’t worry about it. The last one said there’s usually a little play, but that the sound is normal on an older vehicle.