Brand New 7290 U-Joint Failure

If the u-joint has a grease fitting in a "corner", in between the u-joint caps, it needs to be in compression as the driveshaft turns. I also had a failure when an OEM yoke began to spread. It happens after a lot of abuse, but just a bit was enough to hammer the u-joint out and break. This was around 15 years ago. Last, but not least, if everything was installed correctly, it could be the quality/metalurgy of the product.

I use billet steel yokes with u-bolts and solid Spicer u-joints. I haven't had a failure since then even though it was "only" a 7260 or 7260/1330 combo joint. I have a best of 1.47 60' times at 3,540+ lbs footbraking a 360. Traction, weight & torque will eventually find the weak link in your drivetrain. The 4 speed doesn't help either with the "shock". Ring & pinion teeth, then the caps are the normal "weak links" in that order, in the driveline chain.