Question about a 9.25 rear

This isn't for our Dart, but my wife's 2000 Durango has a pinion yoke on the rear axle that is grooved and is leaking. I talked to two different auto parts stores about a sleeve for a pinion yoke like you can get for a harmonic balancer but they didn't know what I was talking about. Does anyone know where I can get one, if one is even available? A new yoke is around $125-$150.