This week, Jarrett from CRAWL TV gets into the nitty-gritty of a common but often misdiagnosed u-joint failure, sponsored by Tom Wood’s Custom Driveshafts.
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Universal Joints are all over our vehicles. If you’ve been involved in the Jeep world long enough, you know how to spot a bad one, how to replace it, and how to maintain them to avoid premature wear or unexpected failures.
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While speaking with Shawn, from Tom Wood’s Custom driveshafts, he taught me something that I never knew about u-joint failure and it seemed like a valuable enough tech lesson that I could share it on CRAWL TV to help educate others. To aid in my demonstration, he also sent out a failed u-joint on a YJ rear driveshaft that had a glaringly obvious example of the problem we were discussing.
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In this quick video, I discuss in my own words what Shawn explained to be about u-joint failure in only one axis of rotation and what causes it. Sure, there are plenty of ways to blow out a universal joint on a vehicle, but this specific failure usually points toward one single part that is commonly overlooked.
What I learned and explained is that this type of failure is not caused by a bad u-joint, but rather a bad attaching yoke. The bores or “saddles” into which a joint attach need to be very perfectly machined surfaces. Sometimes these surfaces will get damaged; this can be because of a joint breaking and damaging the yoke in the process or just because of years of hard use.