So This is Why It Goes "Clunk!"

[colnago]

I think the photo says it all. The good ends were connected to the slip joint on my C6, the munched ends were connected to the connecting shaft. Good thing I needed to get a new connecting shaft anyway!

Joseph

U-Joint 2.jpg

[Jacksdad]

Okay, I thought my UJs were bad when I found I'd lost the needle bearings in one, but you have me beat by a mile. And them some.

Yes, you definitely found the source of at least one clunk. But it's a bump. There's always going to be another somewhere

[sargentrs]

Ouch! Close call on that one.

[Mancar1]

Ok the photo pushed me to action.
Been going to replace the u joints in the 68 CS for a while now. Think I will getter done.
Thanks Joseph, and Keep on Trucking...........John.

[Lee]

Hi,

By chance are the failed ends,... the ends that are secured with the U-bolts?

Reason I ask is because I have had a similar failure with fairly new U-joints. The reason was I was over tightening the U-bolts, crushing the needle bearing caps.

Take care,
Lee

[colnago]

By chance are the failed ends,... the ends that are secured with the U-bolts?

In my case, I had a slip yoke coming out from the C6 transmission, and it didn’t use U-bolts. Neither did the coupling shaft. The C6 had a long tailshaft, and the coupling shaft was only 2" in diameter, so I'm wondering if the whole thing came out of a car. Also, the U-joint is the smaller 1310, not the 1330 that should be in a 3/4-ton truck. I figure that I probably had less than a month before it completely dissolved on me.

Good to know about overtightening the U-bolts. I'm putting in a different C6, and it does use the U-bolts. I can definitely see myself crunching down with a wrench, to make sure it's not loose.

Joseph

[Manny]

Wow just saw those man talking about paper thin!!!

[Dr Farnsworth]

Get a tire up in the air and rotate the driveshaft back and forth by hand while you have the truck in gear or park (motor off and on a jack stand). Look and and feel for any movement on each of the U-joints. If there is any movement you need to replace the joint.
Replace if the U-joint won't take any grease. It can be a sign of rust or contamination in the U-joint.

Unfortunately, this does not work 100% of the time, so use any random excuse as a reason to replace a U-joint.

I had a front one fail on me years ago, it destroyed the ENTIRE drive-train, engine, all the way to the rear axle.

[Ohiotinkerer]

Get a tire up in the air and rotate the driveshaft back and forth by hand while you have the truck in gear or park (motor off and on a jack stand). Look and and feel for any movement on each of the U-joints. If there is any movement you need to replace the joint.
Replace if the U-joint won't take any grease. It can be a sign of rust or contamination in the U-joint.

Unfortunately, this does not work 100% of the time, so use any random excuse as a reason to replace a U-joint.

I had a front one fail on me years ago, it destroyed the ENTIRE drive-train, engine, all the way to the rear axle.

After losing a rear one between Cheyenne and Rawlins Wyoming years ago when I would go to visit family in Idaho I ALWAYS replace them on any vehicle I get that has them no matter they look good and/or take grease......there is nothing between those 2 cities and did manage to limp it (at 40 mph on I-80) into Rawlins where it cost me $140 to have both u joints replaced...... After that experience I look at it as cheap insurance and piece of mind.........