Back the nut all the way off, and see if the seal between the nut and the pivot ball is damaged or missing. Those are still available, and I believe some of them have a diagonal cut that allows the gasket to be installed without dismantling the entire torque tube/universal joint assembly.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!