I too, finally tackled this project on my original 1946. Mine was "seeping" at the front of the ball collar, the rear of the collar and the end of the retainer.
After breaking the u-joint apart, I found that only one shim had been used at the front of the collar, the gasket at the rear of the collar was totally absent. In the retainer, I had some resemblance of an old gasket in between the two metal rings.
Using Best's kit 5151 (I am a big cheerleader of Best Gaskets), both the retainer and rear collar seals went in as planned. Both were coated with oil prior to installation which made them slip into place more easily that if they had been dry. We ended up using 2 shims between the collar and the transmission housing and we used a small mount of gasket sealer on those before bolting everything up.
In my case, the u-joint was in very good shape, but we did replace the bolts and lock tabs (cheap insurance). We added some gear oil through the speedometer housing hole to lube everything up before driving the first time after the repair.
I will also say that we polished and cleaned the ball, collar and inside of the retainer before reassembly.
From start to finish, 2 1/2 hour job. Everything went back together without a hitch. After finishing, we drove the truck for 25 miles. Once parked back in the garage, checked everything..."dry as a bone" in all three areas that previously had leaked.
Get and use the Best Gasket kit, take your time and clean/polish as you go. You will be very happy with the results.
