U-joint Life

Broncobowsher said:

Yoke out of round. You may have a gakked yoke from prior damage and now it keeps damaging new joints.

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I had the same issue, except much shorter life(3-4 months at best). New yoke and over 3 years now without a peep from the same ujoint (and I still have axle wrap). Never would have imagined that would fix it.

Local Bronco friend bought his '76 brand new, and from almost-new it went through rear u-joints about every 5 to 8 thousand miles. Literally 40+ years and however many miles, and who-knows-how-many u-joints later, and he finally fixed it just a few months ago.
Found out that when he took it in for some warranty work on the rear end the first month of ownership and they replaced his whole housing, nobody ever noticed the misaligned pinion.

And in all those years he never noticed any unusual vibrations. Probably in part because he didn't know what to compare it to, but also in part because the vibrations must have been very small.
After correcting the pinion angle we're still waiting to see if they last longer. But even though the jury is still out, confidence is very high.

Even though there are plenty of other potential culprits in your case still, it doesn't cost anything to verify your pinion angle is correct. If you've seen enough of them, you can tell just by looking at it if it's going to be a problem or not.

Paul

it does happen for sure..

So I changed that U-joint. The two sides with U-bolts were completely gone, the other two were fine. Does this mean I just had the U-bolts too tight? Is an out of round yoke still a potential? Thanks!

Wrong yoke on the axle. Bad yoke on the axle. U-bolts too tight. The U-bolts are not transmitting power. They only keep the joint from falling out. If everything were perfect you could just about use a zip tie to hold the U-joint in place (probably wouldn't survive vibrations, road impacts, etc.). So too tight, often a problem. Short finger, one finger pulling on the wrench, that is as tight as it should be. Long wrench and a full handed grab, probably too tight.

With multiple failures I would change the yolk. Not saying too tight isn’t the issue but you really have to try to get them that much too tight multiple times

Just as an example with the long drivetrain... I ran a 351W with a ZF/NP203/D20 with stock WB for 12 years w/o any ujoint wear. Got a Canadian buddy still running his w/o any issues...he's at 20+ years and drives his probably more than I do mine now- both DD drivers.

You can be running a 4 banger and have plenty of axle wrap to kill a ujoint on one day...if your springs are wrapping up when you apply the pedal, it will kill your rear yoke or joints asap.

Put a GoPro underneath and check it out. Excellent ideas posted already-check them all out.

Yeller said:

With multiple failures I would change the yolk. Not saying too tight isn’t the issue but you really have to try to get them that much too tight multiple times

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I'd probably do the same....