I agree 100% with Hotrod Lincoln, no sense making a mountain out of a mole hill.

All you need is the small rubber oil seal at this link.
U-Joint Ball Gasket & Seals

Make sure you have the two O-ring washers.
My retainer only had one.

No sense opening everything up, if the only problem you have is a oil drip.

1954 Chevrolet 3105 Deluxe Panel Truck
w/Factory HYDRA-MATIC