Repeatedly bad u joint

JAKRANCH · Jan 16, 2023

So I just blew the u joint that connects the axle to the driveshaft for the third time in probably 1500 or less miles, this last time I had the driveshaft rebuilt and balanced, that was certainly less than 500 miles ago. I replaced leaf springs and mounts several years ago after a tbone wreck and it seemed that everything was lined up and square. My guess is the wreck tweaked something just enough to put too much pressure on that u joint.
At this point this particular truck is probably done, I don't have the time or funds to figure out what's fubarred. Just curious on any theories y'all might have.

Nero · Jan 16, 2023

Driveline angles, improper installation, no lube, over torque retaining caps... Doubt it would be driveline length, because the driveline would be ramming at the slip, either at the t case, or the slip in a 2 piece driveline.

franklin2 · Jan 16, 2023

JAKRANCH said:
So I just blew the u joint that connects the axle to the driveshaft for the third time in probably 1500 or less miles, this last time I had the driveshaft rebuilt and balanced, that was certainly less than 500 miles ago. I replaced leaf springs and mounts several years ago after a tbone wreck and it seemed that everything was lined up and square. My guess is the wreck tweaked something just enough to put too much pressure on that u joint.
At this point this particular truck is probably done, I don't have the time or funds to figure out what's fubarred. Just curious on any theories y'all might have.

Does it have a lift? I am running a 4 inch lift no problems. Higher than that though, may take the joint to the limit.

u2slow · Jan 16, 2023

Something is off for sure. Need more info on the setup. Or there's damaged parts. Or some other parts mismatch. Is there a driveshaft support bearing?

Even mismatched angles will typically last much longer that OP is experiencing.

Clb · Jan 16, 2023

Per your rundown...
Pinnion yolk *****, frame alignment,rear axle/leaf spring alignment ,first things I thought of.
What are the pinion/tailshaft angles?
Carolina squat?
Trans mount squared away?

hacked89 · Jan 16, 2023

You must be registered for see images attach

JAKRANCH · Jan 16, 2023

Stock suspension on 33s yes on drive shaft carrier bearing, brand new when I had the driveshaft rebuilt. U joint was new and lubed up but not over lubed, tranny mount is square, truck travels straight down the road. Leaf spring are newly replaced . To the best I and several mechanically inclined buddies and the driveline shop can tell all components are aligned. How much is too much pinion angle? Naked eye hey that don't look right? Or half a degree off and your burning out u joints?

JAKRANCH · Jan 16, 2023

And Carolina squats are gross in my opinion lol

JAKRANCH · Jan 16, 2023

Not the best pic for under the bed but only one I have on my phone right now. When it blew we where pushing up a big hill with one horse in a bumper pull trailer on the free way.

CDX825 · Jan 17, 2023

How are they failing?

JAKRANCH · Jan 17, 2023

Shearing out of the axle side

Austin86250 · Jan 17, 2023

JAKRANCH said:
Shearing out of the axle side

Try a non grease able they are stronger

Nero · Jan 17, 2023

I don't think that's the issue, I have greasable in my crew cab and no issues in years...

Booyah45828 · Jan 17, 2023

Any pictures? How's the needles look? Too much of an angle will give a harmonic shake and noise, same with mismatched angles. Too little of an angle and the joint doesn't move enough and the needles will pound flat and then fail, especially if your loaded heavy.

Put an angle finder on it see what you come up with. But there's a very real reason this is failing, you just have to find it.

JAKRANCH · Jan 17, 2023

The failures have all been under acceleration loaded, twice with pretty steep hills

Repeatedly bad u joint

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