[leegreen]

I had a similar problem with a off topic SUV, The nut holding the spline together would not stay tight, when it loosened driveline vibrations would set in. Replacement parts for this specific model were hand forged by elves out of unicorn whiskers and cost more than the SUV was worth.

I tightened the nut, welded the nut to the splined shaft and the splined yoke to the nut. Problem solved. At least the immediate problem was solved. If it had not been rear ended a couple years later eventually I would have had a larger problem when something needed servicing.