Blew a U-Joint while driving

[Hombre909]

‘O3 Pathfinder LE, stock suspension. So, gf was cruising along at about 70mph, when she heard the bang, then metal on metal grinding. Pulled right over, fortunately. Front U-joint of the rear shaft blew at least one its four covers, exposing the needle bearings. Next day, four mechanics couldn't figure out why it blew, except for the retaining clips that were missing, but lubrication was fine, and as a kicker, I just replaced both front and back joints two months ago. After ordering the wrong part, the joint was installed, and gf drove 1.5 hours home without incident. I checked the joint and could see no ret. clips, and the trunnions are nearly flush with the yoke. They did use red Loctite on the trunnion caps, and there’s absolutely no play in the shaft. Gonna argue for a refund from the first shop and have the blown joint for proof. But the new shop is no help if they're asked their opinion. Missing clips the sole reason?

[Mike W.]

I'd say the missing clips are the problem. I mean they're there for a reason and most bearings that are even pressed fit still use some sort of retainer. BMW for instance doesn't use clips on the U joints, but instead stakes them in place preventing cap movement. Makes replacement much more difficult, but same principal, a mechanical lock, not just friction.